From e24f311d5ca9dae93e2db2c94f0eb928881602ce Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Thu, 18 Oct 2018 17:06:18 -0400
Subject: [PATCH 01/21] Implement fetchAllMiddleware to handle per_page=-1
 through pagination

Introduce a new middleware function to iterate through all available pages
for a large collection, replacing any encountered `per_page=-1` requests
with a series of sequential requests which are assembled into a final
merged array of all available results.
---
 packages/api-fetch/src/index.js | 80 ++++++++++++++++++++++++++++-----
 1 file changed, 70 insertions(+), 10 deletions(-)

diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index a2ebeeff37a9a9..1e9563969b6c7a 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -26,9 +26,17 @@ function checkCloudflareError( error ) {
 	}
 }
 
+function parseResponse( response, parse = true ) {
+	if ( parse ) {
+		return response.json ? response.json() : Promise.reject( response );
+	}
+
+	return response;
+}
+
 function apiFetch( options ) {
 	const raw = ( nextOptions ) => {
-		const { url, path, body, data, parse = true, ...remainingOptions } = nextOptions;
+		const { url, path, body, data, parse, ...remainingOptions } = nextOptions;
 		const headers = remainingOptions.headers || {};
 		if ( ! headers[ 'Content-Type' ] && data ) {
 			headers[ 'Content-Type' ] = 'application/json';
@@ -51,17 +59,9 @@ function apiFetch( options ) {
 			throw response;
 		};
 
-		const parseResponse = ( response ) => {
-			if ( parse ) {
-				return response.json ? response.json() : Promise.reject( response );
-			}
-
-			return response;
-		};
-
 		return responsePromise
 			.then( checkStatus )
-			.then( parseResponse )
+			.then( ( response ) => parseResponse( response, parse ) )
 			.catch( ( response ) => {
 				if ( ! parse ) {
 					throw response;
@@ -119,6 +119,66 @@ function apiFetch( options ) {
 
 apiFetch.use = registerMiddleware;
 
+const capPerPageQuery = ( options ) => ( {
+	...options,
+	// Swap back to requesting the max of 100 items per page.
+	// TODO: This feels brittle. Is there a better way to manage request parameters?
+	path: options.path && `${ options.path.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
+	url: options.url && `${ options.url.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
+} );
+
+const setRequestedPage = ( options, page ) => ( {
+	...options,
+	path: options.path && options.path.replace( '&page=1', `&page=${ page }` ),
+	url: options.url && options.url.replace( '&page=1', `&page=${ page }` ),
+} );
+
+// The REST API enforces an upper limit of 100 on the per_page option. To handle
+// large collections, apiFetch consumers can pass `per_page=-1` and this middleware
+// function will recursively assemble a full response by paging over all available
+// pages of API data.
+const fetchAllMiddleware = async ( options, next ) => {
+	try {
+		if ( options.url && options.url.indexOf( 'per_page=-1' ) < 0 ) {
+			return next( options );
+		}
+
+		const pageOptions = capPerPageQuery( options );
+		const pageOneResults = await next( {
+			...pageOptions,
+			// Ensure headers are returned for page 1.
+			parse: false,
+		} );
+		const pageOneParsed = await parseResponse( pageOneResults, options.parse );
+
+		const totalPages = pageOneResults.headers && pageOneResults.headers.get( 'X-WP-TotalPages' );
+
+		// Build an array of options objects for each remaining page.
+		const remainingPageRequests = Array.from( {
+			length: totalPages - 1,
+		} ).map( ( _, idx ) => {
+			// Specify the page to request. First additional request is index 0 but page 2, etc.
+			// Build these URLs based on pageOptions to avoid repeating the per_page adjustment.
+			return setRequestedPage( pageOptions, idx + 2 );
+		} );
+
+		return remainingPageRequests.reduce(
+			// Request each remaining page in sequence, and return a merged array.
+			async ( previousPageRequest, nextPageOptions ) => {
+				const resultsCollection = await previousPageRequest;
+				const nextPage = await apiFetch( nextPageOptions );
+				return resultsCollection.concat( nextPage );
+			},
+			// Ensure that the first page is parsed properly, as specified in the original options.
+			[].concat( pageOneParsed )
+		);
+	} catch ( e ) {
+		return Promise.reject( e );
+	}
+};
+
+apiFetch.use( fetchAllMiddleware );
+
 apiFetch.createNonceMiddleware = createNonceMiddleware;
 apiFetch.createPreloadingMiddleware = createPreloadingMiddleware;
 apiFetch.createRootURLMiddleware = createRootURLMiddleware;

From a3f3517af7947f2cb9e5c00455fbad7229508384 Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Thu, 18 Oct 2018 17:48:42 -0400
Subject: [PATCH 02/21] Move fetchAllMiddleware to its own module

---
 packages/api-fetch/src/index.js               | 62 +---------------
 .../src/middlewares/fetch-all-middleware.js   | 71 +++++++++++++++++++
 2 files changed, 73 insertions(+), 60 deletions(-)
 create mode 100644 packages/api-fetch/src/middlewares/fetch-all-middleware.js

diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index 1e9563969b6c7a..aa73db04820858 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -9,6 +9,7 @@ import { __ } from '@wordpress/i18n';
 import createNonceMiddleware from './middlewares/nonce';
 import createRootURLMiddleware from './middlewares/root-url';
 import createPreloadingMiddleware from './middlewares/preloading';
+import fetchAllMiddleware from './middlewares/fetch-all-middleware';
 import namespaceEndpointMiddleware from './middlewares/namespace-endpoint';
 import httpV1Middleware from './middlewares/http-v1';
 
@@ -107,6 +108,7 @@ function apiFetch( options ) {
 		raw,
 		httpV1Middleware,
 		namespaceEndpointMiddleware,
+		fetchAllMiddleware,
 		...middlewares,
 	];
 	const next = ( nextOptions ) => {
@@ -119,66 +121,6 @@ function apiFetch( options ) {
 
 apiFetch.use = registerMiddleware;
 
-const capPerPageQuery = ( options ) => ( {
-	...options,
-	// Swap back to requesting the max of 100 items per page.
-	// TODO: This feels brittle. Is there a better way to manage request parameters?
-	path: options.path && `${ options.path.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
-	url: options.url && `${ options.url.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
-} );
-
-const setRequestedPage = ( options, page ) => ( {
-	...options,
-	path: options.path && options.path.replace( '&page=1', `&page=${ page }` ),
-	url: options.url && options.url.replace( '&page=1', `&page=${ page }` ),
-} );
-
-// The REST API enforces an upper limit of 100 on the per_page option. To handle
-// large collections, apiFetch consumers can pass `per_page=-1` and this middleware
-// function will recursively assemble a full response by paging over all available
-// pages of API data.
-const fetchAllMiddleware = async ( options, next ) => {
-	try {
-		if ( options.url && options.url.indexOf( 'per_page=-1' ) < 0 ) {
-			return next( options );
-		}
-
-		const pageOptions = capPerPageQuery( options );
-		const pageOneResults = await next( {
-			...pageOptions,
-			// Ensure headers are returned for page 1.
-			parse: false,
-		} );
-		const pageOneParsed = await parseResponse( pageOneResults, options.parse );
-
-		const totalPages = pageOneResults.headers && pageOneResults.headers.get( 'X-WP-TotalPages' );
-
-		// Build an array of options objects for each remaining page.
-		const remainingPageRequests = Array.from( {
-			length: totalPages - 1,
-		} ).map( ( _, idx ) => {
-			// Specify the page to request. First additional request is index 0 but page 2, etc.
-			// Build these URLs based on pageOptions to avoid repeating the per_page adjustment.
-			return setRequestedPage( pageOptions, idx + 2 );
-		} );
-
-		return remainingPageRequests.reduce(
-			// Request each remaining page in sequence, and return a merged array.
-			async ( previousPageRequest, nextPageOptions ) => {
-				const resultsCollection = await previousPageRequest;
-				const nextPage = await apiFetch( nextPageOptions );
-				return resultsCollection.concat( nextPage );
-			},
-			// Ensure that the first page is parsed properly, as specified in the original options.
-			[].concat( pageOneParsed )
-		);
-	} catch ( e ) {
-		return Promise.reject( e );
-	}
-};
-
-apiFetch.use( fetchAllMiddleware );
-
 apiFetch.createNonceMiddleware = createNonceMiddleware;
 apiFetch.createPreloadingMiddleware = createPreloadingMiddleware;
 apiFetch.createRootURLMiddleware = createRootURLMiddleware;
diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
new file mode 100644
index 00000000000000..0c9c060f5a5332
--- /dev/null
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -0,0 +1,71 @@
+import apiFetch from '../';
+
+// Duplicates parsing functionality from apiFetch.
+function parseResponse( response, parse = true ) {
+	if ( parse ) {
+		return response.json ? response.json() : Promise.reject( response );
+	}
+
+	return response;
+}
+
+const capPerPageQuery = ( options ) => ( {
+	...options,
+	// Swap back to requesting the max of 100 items per page.
+	// TODO: This feels brittle. Is there a better way to manage request parameters?
+	path: options.path && `${ options.path.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
+	url: options.url && `${ options.url.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
+} );
+
+const setRequestedPage = ( options, page ) => ( {
+	...options,
+	path: options.path && options.path.replace( '&page=1', `&page=${ page }` ),
+	url: options.url && options.url.replace( '&page=1', `&page=${ page }` ),
+} );
+
+// The REST API enforces an upper limit of 100 on the per_page option. To handle
+// large collections, apiFetch consumers can pass `per_page=-1` and this middleware
+// function will recursively assemble a full response by paging over all available
+// pages of API data.
+const fetchAllMiddleware = async ( options, next ) => {
+	try {
+		if ( options.url && options.url.indexOf( 'per_page=-1' ) < 0 ) {
+			return next( options );
+		}
+
+		const pageOptions = capPerPageQuery( options );
+		const pageOneResults = await next( {
+			...pageOptions,
+			// Ensure headers are returned for page 1.
+			parse: false,
+		} );
+		const pageOneParsed = await parseResponse( pageOneResults, options.parse );
+
+		const totalPages = pageOneResults.headers && pageOneResults.headers.get( 'X-WP-TotalPages' );
+
+		// Build an array of options objects for each remaining page.
+		const remainingPageRequests = Array.from( {
+			length: totalPages - 1,
+		} ).map( ( _, idx ) => {
+			// Specify the page to request. First additional request is index 0 but page 2, etc.
+			// Build these URLs based on pageOptions to avoid repeating the per_page adjustment.
+			return setRequestedPage( pageOptions, idx + 2 );
+		} );
+
+		return remainingPageRequests.reduce(
+			// Request each remaining page in sequence, and return a merged array.
+			async ( previousPageRequest, nextPageOptions ) => {
+				const resultsCollection = await previousPageRequest;
+				// TODO: Circular dependency
+				const nextPage = await apiFetch( nextPageOptions );
+				return resultsCollection.concat( nextPage );
+			},
+			// Ensure that the first page is parsed properly, as specified in the original options.
+			[].concat( pageOneParsed )
+		);
+	} catch ( e ) {
+		return Promise.reject( e );
+	}
+};
+
+export default fetchAllMiddleware;

From 0b132846cc6cb44adc3f6333f1de80a951367f5c Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Thu, 18 Oct 2018 17:54:51 -0400
Subject: [PATCH 03/21] Use @wordpress/url module to modify query strings
 within fetchAllMiddleware

---
 lib/client-assets.php                         |  2 +-
 packages/api-fetch/package.json               |  3 ++-
 .../src/middlewares/fetch-all-middleware.js   | 27 +++++++++++++++----
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/lib/client-assets.php b/lib/client-assets.php
index 7f1e3b48938bbd..b9b2f10037262c 100644
--- a/lib/client-assets.php
+++ b/lib/client-assets.php
@@ -231,7 +231,7 @@ function gutenberg_register_scripts_and_styles() {
 	gutenberg_override_script(
 		'wp-api-fetch',
 		gutenberg_url( 'build/api-fetch/index.js' ),
-		array( 'wp-polyfill', 'wp-hooks', 'wp-i18n' ),
+		array( 'wp-polyfill', 'wp-hooks', 'wp-i18n', 'wp-url' ),
 		filemtime( gutenberg_dir_path() . 'build/api-fetch/index.js' ),
 		true
 	);
diff --git a/packages/api-fetch/package.json b/packages/api-fetch/package.json
index ed66f99b0444eb..bf5ed7b10f8f08 100644
--- a/packages/api-fetch/package.json
+++ b/packages/api-fetch/package.json
@@ -23,7 +23,8 @@
 	"dependencies": {
 		"@babel/runtime": "^7.0.0",
 		"@wordpress/hooks": "file:../hooks",
-		"@wordpress/i18n": "file:../i18n"
+		"@wordpress/i18n": "file:../i18n",
+		"@wordpress/url": "file:../url"
 	},
 	"publishConfig": {
 		"access": "public"
diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 0c9c060f5a5332..42a3cc7948a24f 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -1,3 +1,11 @@
+/**
+ * WordPress dependencies
+ */
+import { addQueryArgs } from '@wordpress/url';
+
+/**
+ * Internal dependencies
+ */
 import apiFetch from '../';
 
 // Duplicates parsing functionality from apiFetch.
@@ -12,15 +20,24 @@ function parseResponse( response, parse = true ) {
 const capPerPageQuery = ( options ) => ( {
 	...options,
 	// Swap back to requesting the max of 100 items per page.
-	// TODO: This feels brittle. Is there a better way to manage request parameters?
-	path: options.path && `${ options.path.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
-	url: options.url && `${ options.url.replace( /(\&?per_page)=-1/, '$1=100' ) }&page=1`,
+	path: options.path && addQueryArgs( options.path, {
+		per_page: 100,
+		page: 1,
+	} ),
+	url: options.url && addQueryArgs( options.url, {
+		per_page: 100,
+		page: 1,
+	} ),
 } );
 
 const setRequestedPage = ( options, page ) => ( {
 	...options,
-	path: options.path && options.path.replace( '&page=1', `&page=${ page }` ),
-	url: options.url && options.url.replace( '&page=1', `&page=${ page }` ),
+	path: options.path && addQueryArgs( options.path, {
+		page,
+	} ),
+	url: options.url && addQueryArgs( options.url, {
+		page,
+	} ),
 } );
 
 // The REST API enforces an upper limit of 100 on the per_page option. To handle

From c54aa57fd6f0bf02d3f1474de26b24b55a25903e Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Thu, 18 Oct 2018 22:26:52 -0400
Subject: [PATCH 04/21] Make fetchAllMiddleware optional within apiFetch and
 add it with inline script

---
 lib/client-assets.php           | 5 +++++
 packages/api-fetch/src/index.js | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/client-assets.php b/lib/client-assets.php
index b9b2f10037262c..e7f00817f92b03 100644
--- a/lib/client-assets.php
+++ b/lib/client-assets.php
@@ -251,6 +251,11 @@ function gutenberg_register_scripts_and_styles() {
 		),
 		'after'
 	);
+	wp_add_inline_script(
+		'wp-api-fetch',
+		'wp.apiFetch.use( wp.apiFetch.fetchAllMiddleware );',
+		'after'
+	);
 
 	gutenberg_override_script(
 		'wp-deprecated',
diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index aa73db04820858..c00f0d6552d212 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -108,7 +108,6 @@ function apiFetch( options ) {
 		raw,
 		httpV1Middleware,
 		namespaceEndpointMiddleware,
-		fetchAllMiddleware,
 		...middlewares,
 	];
 	const next = ( nextOptions ) => {
@@ -124,5 +123,6 @@ apiFetch.use = registerMiddleware;
 apiFetch.createNonceMiddleware = createNonceMiddleware;
 apiFetch.createPreloadingMiddleware = createPreloadingMiddleware;
 apiFetch.createRootURLMiddleware = createRootURLMiddleware;
+apiFetch.fetchAllMiddleware = fetchAllMiddleware;
 
 export default apiFetch;

From ed69cb59ff8af2c312e4efb0898954cfa79e09d1 Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Thu, 18 Oct 2018 23:27:08 -0400
Subject: [PATCH 05/21] Improve comments for fetchAllMiddleware module

---
 .../src/middlewares/fetch-all-middleware.js      | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 42a3cc7948a24f..ffaad8f5ac6f58 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -19,7 +19,7 @@ function parseResponse( response, parse = true ) {
 
 const capPerPageQuery = ( options ) => ( {
 	...options,
-	// Swap back to requesting the max of 100 items per page.
+	// Swap back to requesting the max number of items per page.
 	path: options.path && addQueryArgs( options.path, {
 		per_page: 100,
 		page: 1,
@@ -40,10 +40,9 @@ const setRequestedPage = ( options, page ) => ( {
 	} ),
 } );
 
-// The REST API enforces an upper limit of 100 on the per_page option. To handle
-// large collections, apiFetch consumers can pass `per_page=-1` and this middleware
-// function will recursively assemble a full response by paging over all available
-// pages of API data.
+// The REST API enforces an upper limit on the per_page option. To handle large
+// collections, apiFetch consumers can pass `per_page=-1`; this middleware will
+// then recursively assemble a full response array from all available pages.
 const fetchAllMiddleware = async ( options, next ) => {
 	try {
 		if ( options.url && options.url.indexOf( 'per_page=-1' ) < 0 ) {
@@ -56,7 +55,6 @@ const fetchAllMiddleware = async ( options, next ) => {
 			// Ensure headers are returned for page 1.
 			parse: false,
 		} );
-		const pageOneParsed = await parseResponse( pageOneResults, options.parse );
 
 		const totalPages = pageOneResults.headers && pageOneResults.headers.get( 'X-WP-TotalPages' );
 
@@ -65,19 +63,19 @@ const fetchAllMiddleware = async ( options, next ) => {
 			length: totalPages - 1,
 		} ).map( ( _, idx ) => {
 			// Specify the page to request. First additional request is index 0 but page 2, etc.
-			// Build these URLs based on pageOptions to avoid repeating the per_page adjustment.
 			return setRequestedPage( pageOptions, idx + 2 );
 		} );
 
+		// Ensure the first page is parsed as specified.
+		const pageOneParsed = await parseResponse( pageOneResults, options.parse );
+
 		return remainingPageRequests.reduce(
 			// Request each remaining page in sequence, and return a merged array.
 			async ( previousPageRequest, nextPageOptions ) => {
 				const resultsCollection = await previousPageRequest;
-				// TODO: Circular dependency
 				const nextPage = await apiFetch( nextPageOptions );
 				return resultsCollection.concat( nextPage );
 			},
-			// Ensure that the first page is parsed properly, as specified in the original options.
 			[].concat( pageOneParsed )
 		);
 	} catch ( e ) {

From 49d80cdbd15068306db57cbd87aa808467d3e908 Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Fri, 19 Oct 2018 15:33:27 -0400
Subject: [PATCH 06/21] Improve fetchAllMiddleware: use links for pagination.

- Remove unneeded modification to apiFetch parsing logic.
- Utilize the links header to traverse collection pages.
- Remove confusing try/catch behavior.
- Add more escape hatches for cases where middleware should not apply.
---
 packages/api-fetch/src/index.js               |  16 +--
 .../src/middlewares/fetch-all-middleware.js   | 133 ++++++++++--------
 2 files changed, 82 insertions(+), 67 deletions(-)

diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index c00f0d6552d212..bbea7c3d1378fb 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -27,14 +27,6 @@ function checkCloudflareError( error ) {
 	}
 }
 
-function parseResponse( response, parse = true ) {
-	if ( parse ) {
-		return response.json ? response.json() : Promise.reject( response );
-	}
-
-	return response;
-}
-
 function apiFetch( options ) {
 	const raw = ( nextOptions ) => {
 		const { url, path, body, data, parse, ...remainingOptions } = nextOptions;
@@ -62,7 +54,13 @@ function apiFetch( options ) {
 
 		return responsePromise
 			.then( checkStatus )
-			.then( ( response ) => parseResponse( response, parse ) )
+			.then( ( response ) => {
+				if ( parse ) {
+					return response.json ? response.json() : Promise.reject( response );
+				}
+
+				return response;
+			} )
 			.catch( ( response ) => {
 				if ( ! parse ) {
 					throw response;
diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index ffaad8f5ac6f58..4d427523fa8909 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -1,3 +1,4 @@
+/* eslint-disable no-console */
 /**
  * WordPress dependencies
  */
@@ -8,79 +9,95 @@ import { addQueryArgs } from '@wordpress/url';
  */
 import apiFetch from '../';
 
+// Apply query arguments to both URL and Path, whichever is present.
+const modifyQuery = ( { path, url, ...options }, queryArgs ) => ( {
+	...options,
+	...( url ? {
+		url: addQueryArgs( url || path, queryArgs ),
+	} : {} ),
+	...( path ? {
+		path: addQueryArgs( path || path, queryArgs ),
+	} : {} ),
+} );
+
 // Duplicates parsing functionality from apiFetch.
-function parseResponse( response, parse = true ) {
-	if ( parse ) {
-		return response.json ? response.json() : Promise.reject( response );
-	}
+const parseResponse = ( response ) => response.json ?
+	response.json() :
+	Promise.reject( response );
 
-	return response;
-}
+const parseLinkHeader = ( linkHeader ) => {
+	if ( ! linkHeader ) {
+		return {};
+	}
+	const match = linkHeader.match( /<([^>]+)>; rel="next"/ );
+	return match ? {
+		next: match[ 1 ],
+	} : {};
+};
 
-const capPerPageQuery = ( options ) => ( {
-	...options,
-	// Swap back to requesting the max number of items per page.
-	path: options.path && addQueryArgs( options.path, {
-		per_page: 100,
-		page: 1,
-	} ),
-	url: options.url && addQueryArgs( options.url, {
-		per_page: 100,
-		page: 1,
-	} ),
-} );
+const getNextPageUrl = ( response ) => {
+	const { next } = parseLinkHeader( response.headers.get( 'link' ) );
+	return next;
+};
 
-const setRequestedPage = ( options, page ) => ( {
-	...options,
-	path: options.path && addQueryArgs( options.path, {
-		page,
-	} ),
-	url: options.url && addQueryArgs( options.url, {
-		page,
-	} ),
-} );
+const requestContainsUnboundedQuery = ( options ) => {
+	const pathIsUnbounded = options.path && options.path.indexOf( 'per_page=-1' > -1 );
+	const urlIsUnbounded = options.url && options.url.indexOf( 'per_page=-1' > -1 );
+	return pathIsUnbounded || urlIsUnbounded;
+};
 
 // The REST API enforces an upper limit on the per_page option. To handle large
 // collections, apiFetch consumers can pass `per_page=-1`; this middleware will
 // then recursively assemble a full response array from all available pages.
 const fetchAllMiddleware = async ( options, next ) => {
-	try {
-		if ( options.url && options.url.indexOf( 'per_page=-1' ) < 0 ) {
-			return next( options );
-		}
+	if ( options.parse === false ) {
+		// If a consumer has opted out of parsing, do not apply middleware.
+		return next( options );
+	}
+	if ( ! requestContainsUnboundedQuery( options ) ) {
+		// If neither url nor path is requesting all items, do not apply middleware.
+		return next( options );
+	}
 
-		const pageOptions = capPerPageQuery( options );
-		const pageOneResults = await next( {
-			...pageOptions,
-			// Ensure headers are returned for page 1.
-			parse: false,
-		} );
+	// Retrieve requested page of results.
+	const response = await next( {
+		...modifyQuery( options, {
+			per_page: 100,
+		} ),
+		// Ensure headers are returned for page 1.
+		parse: false,
+	} );
 
-		const totalPages = pageOneResults.headers && pageOneResults.headers.get( 'X-WP-TotalPages' );
+	const results = await parseResponse( response );
 
-		// Build an array of options objects for each remaining page.
-		const remainingPageRequests = Array.from( {
-			length: totalPages - 1,
-		} ).map( ( _, idx ) => {
-			// Specify the page to request. First additional request is index 0 but page 2, etc.
-			return setRequestedPage( pageOptions, idx + 2 );
-		} );
+	if ( ! Array.isArray( results ) ) {
+		// We have no reliable way of merging non-array results.
+		return results;
+	}
+
+	let nextPage = getNextPageUrl( response );
 
-		// Ensure the first page is parsed as specified.
-		const pageOneParsed = await parseResponse( pageOneResults, options.parse );
+	if ( ! nextPage ) {
+		// There are no further pages to request.
+		return results;
+	}
 
-		return remainingPageRequests.reduce(
-			// Request each remaining page in sequence, and return a merged array.
-			async ( previousPageRequest, nextPageOptions ) => {
-				const resultsCollection = await previousPageRequest;
-				const nextPage = await apiFetch( nextPageOptions );
-				return resultsCollection.concat( nextPage );
-			},
-			[].concat( pageOneParsed )
-		);
-	} catch ( e ) {
-		return Promise.reject( e );
+	// Iteratively fetch all remaining pages until no "next" header is found.
+	let mergedResults = [].concat( results );
+	while ( nextPage ) {
+		const nextResponse = await apiFetch( {
+			...options,
+			// Ensure the URL for the next page is used instead of any provided path.
+			path: undefined,
+			url: nextPage,
+			// Ensure we still get headers so we can identify the next page.
+			parse: false,
+		} );
+		const nextResults = await parseResponse( nextResponse );
+		mergedResults = mergedResults.concat( nextResults );
+		nextPage = getNextPageUrl( nextResponse );
 	}
+	return mergedResults;
 };
 
 export default fetchAllMiddleware;

From c615efd2811d5b0b12dcaacb0892249bbc0e14eb Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Fri, 19 Oct 2018 15:39:12 -0400
Subject: [PATCH 07/21] Remove leftover debugging comment

---
 packages/api-fetch/src/middlewares/fetch-all-middleware.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 4d427523fa8909..0c9dfd30a55c0b 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 /**
  * WordPress dependencies
  */

From d122d8753cd24f91eb4545d8cb0e6046e8c7544a Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Fri, 19 Oct 2018 15:44:35 -0400
Subject: [PATCH 08/21] Apply fetchAllMiddleware within apiFetch, not
 client-scripts.php

---
 lib/client-assets.php           | 5 -----
 packages/api-fetch/src/index.js | 1 +
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/lib/client-assets.php b/lib/client-assets.php
index e7f00817f92b03..b9b2f10037262c 100644
--- a/lib/client-assets.php
+++ b/lib/client-assets.php
@@ -251,11 +251,6 @@ function gutenberg_register_scripts_and_styles() {
 		),
 		'after'
 	);
-	wp_add_inline_script(
-		'wp-api-fetch',
-		'wp.apiFetch.use( wp.apiFetch.fetchAllMiddleware );',
-		'after'
-	);
 
 	gutenberg_override_script(
 		'wp-deprecated',
diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index bbea7c3d1378fb..f63448607a541a 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -104,6 +104,7 @@ function apiFetch( options ) {
 
 	const steps = [
 		raw,
+		fetchAllMiddleware,
 		httpV1Middleware,
 		namespaceEndpointMiddleware,
 		...middlewares,

From e11f34c7fe4716b8f919c927a34d3793b7c592d4 Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Fri, 19 Oct 2018 15:44:51 -0400
Subject: [PATCH 09/21] Simplify obtuse code in query modification logic

---
 .../api-fetch/src/middlewares/fetch-all-middleware.js     | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 0c9dfd30a55c0b..24a67a3633e191 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -11,12 +11,8 @@ import apiFetch from '../';
 // Apply query arguments to both URL and Path, whichever is present.
 const modifyQuery = ( { path, url, ...options }, queryArgs ) => ( {
 	...options,
-	...( url ? {
-		url: addQueryArgs( url || path, queryArgs ),
-	} : {} ),
-	...( path ? {
-		path: addQueryArgs( path || path, queryArgs ),
-	} : {} ),
+	url: url && addQueryArgs( url, queryArgs ),
+	path: path && addQueryArgs( path, queryArgs ),
 } );
 
 // Duplicates parsing functionality from apiFetch.

From 7703ce2d4082a81794b6c03908e36aaf85a34d6f Mon Sep 17 00:00:00 2001
From: "K. Adam White" <kadamwhite@users.noreply.github.com>
Date: Fri, 19 Oct 2018 16:09:05 -0400
Subject: [PATCH 10/21] Fix improperly reverted parsing code change

---
 packages/api-fetch/src/index.js | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index f63448607a541a..4f6b3ce202645a 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -29,7 +29,7 @@ function checkCloudflareError( error ) {
 
 function apiFetch( options ) {
 	const raw = ( nextOptions ) => {
-		const { url, path, body, data, parse, ...remainingOptions } = nextOptions;
+		const { url, path, body, data, parse = true, ...remainingOptions } = nextOptions;
 		const headers = remainingOptions.headers || {};
 		if ( ! headers[ 'Content-Type' ] && data ) {
 			headers[ 'Content-Type' ] = 'application/json';
@@ -52,15 +52,17 @@ function apiFetch( options ) {
 			throw response;
 		};
 
+		const parseResponse = ( response ) => {
+			if ( parse ) {
+				return response.json ? response.json() : Promise.reject( response );
+			}
+
+			return response;
+		};
+
 		return responsePromise
 			.then( checkStatus )
-			.then( ( response ) => {
-				if ( parse ) {
-					return response.json ? response.json() : Promise.reject( response );
-				}
-
-				return response;
-			} )
+			.then( parseResponse )
 			.catch( ( response ) => {
 				if ( ! parse ) {
 					throw response;

From c2c2f6cec00c38fd8c3629b61b4b238d2a6b56f2 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 15:31:10 +0100
Subject: [PATCH 11/21] Fix unit tests

---
 packages/api-fetch/src/middlewares/fetch-all-middleware.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 24a67a3633e191..83e2ef08402d21 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -36,8 +36,8 @@ const getNextPageUrl = ( response ) => {
 };
 
 const requestContainsUnboundedQuery = ( options ) => {
-	const pathIsUnbounded = options.path && options.path.indexOf( 'per_page=-1' > -1 );
-	const urlIsUnbounded = options.url && options.url.indexOf( 'per_page=-1' > -1 );
+	const pathIsUnbounded = options.path && options.path.indexOf( 'per_page=-1' ) !== -1;
+	const urlIsUnbounded = options.url && options.url.indexOf( 'per_page=-1' ) !== -1;
 	return pathIsUnbounded || urlIsUnbounded;
 };
 

From 158f088439d0da54befe2a360e41cb653ca319e0 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 15:35:08 +0100
Subject: [PATCH 12/21] Avoid circular dependency

---
 packages/api-fetch/src/middlewares/fetch-all-middleware.js | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 83e2ef08402d21..5bc17b5413d326 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -3,11 +3,6 @@
  */
 import { addQueryArgs } from '@wordpress/url';
 
-/**
- * Internal dependencies
- */
-import apiFetch from '../';
-
 // Apply query arguments to both URL and Path, whichever is present.
 const modifyQuery = ( { path, url, ...options }, queryArgs ) => ( {
 	...options,
@@ -80,7 +75,7 @@ const fetchAllMiddleware = async ( options, next ) => {
 	// Iteratively fetch all remaining pages until no "next" header is found.
 	let mergedResults = [].concat( results );
 	while ( nextPage ) {
-		const nextResponse = await apiFetch( {
+		const nextResponse = await next( {
 			...options,
 			// Ensure the URL for the next page is used instead of any provided path.
 			path: undefined,

From 5c7a2f2224fdd2f4cd610a2fd55ee7ad61e2965d Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 15:50:36 +0100
Subject: [PATCH 13/21] Adding some unit tests

---
 .../middlewares/test/fetch-all-middleware.js  | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 packages/api-fetch/src/middlewares/test/fetch-all-middleware.js

diff --git a/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js
new file mode 100644
index 00000000000000..930a7d7da970cc
--- /dev/null
+++ b/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js
@@ -0,0 +1,38 @@
+/**
+ * Internal dependencies
+ */
+import fetchAllMiddleware from '../fetch-all-middleware';
+
+describe( 'Fetch All Middleware', async () => {
+	it( 'should defer with the same options to the next middleware', async () => {
+		expect.hasAssertions();
+		const originalOptions = { path: '/posts' };
+		const next = ( options ) => {
+			expect( options ).toBe( originalOptions );
+			return Promise.resolve( 'ok' );
+		};
+
+		await fetchAllMiddleware( originalOptions, next );
+	} );
+
+	it( 'should paginate the request', async () => {
+		expect.hasAssertions();
+		const originalOptions = { path: '/posts?per_page=-1' };
+		const next = ( options ) => {
+			expect( options.path ).toBe( '/posts?per_page=100' );
+			return Promise.resolve( {
+				status: 200,
+				headers: {
+					get() {
+						return '';
+					},
+				},
+				json() {
+					return Promise.resolve( { message: 'ok' } );
+				},
+			} );
+		};
+
+		await fetchAllMiddleware( originalOptions, next );
+	} );
+} );

From b7bb2cd43e6a7b56e346292e0865145c447532aa Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 15:54:50 +0100
Subject: [PATCH 14/21] Remove useless per_page argument

---
 packages/edit-post/src/hooks/components/media-upload/index.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/edit-post/src/hooks/components/media-upload/index.js b/packages/edit-post/src/hooks/components/media-upload/index.js
index 72e223ce66bd52..0e22b6cd5286ec 100644
--- a/packages/edit-post/src/hooks/components/media-upload/index.js
+++ b/packages/edit-post/src/hooks/components/media-upload/index.js
@@ -67,7 +67,6 @@ const getAttachmentsCollection = ( ids ) => {
 	return wp.media.query( {
 		order: 'ASC',
 		orderby: 'post__in',
-		per_page: -1,
 		post__in: ids,
 		query: true,
 		type: 'image',

From 5436e18a9c4f88488dde947b119958e91afb3d7d Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 16:06:38 +0100
Subject: [PATCH 15/21] Update the lock file

---
 package-lock.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/package-lock.json b/package-lock.json
index 1867236d23dc43..179915339a81b5 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2007,7 +2007,8 @@
 			"requires": {
 				"@babel/runtime": "^7.0.0",
 				"@wordpress/hooks": "file:packages/hooks",
-				"@wordpress/i18n": "file:packages/i18n"
+				"@wordpress/i18n": "file:packages/i18n",
+				"@wordpress/url": "file:packages/url"
 			}
 		},
 		"@wordpress/autop": {

From 8803b88e7e7eed8f73aba32b52608175b1a2e858 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 16:08:14 +0100
Subject: [PATCH 16/21] Update api-fetch CHANGELOG

---
 packages/api-fetch/CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/api-fetch/CHANGELOG.md b/packages/api-fetch/CHANGELOG.md
index a49cefcd0d75cf..7d53f6aa2222f8 100644
--- a/packages/api-fetch/CHANGELOG.md
+++ b/packages/api-fetch/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 2.1.0 (Unreleased)
+
+- Support `per_page=-1` paginated requests.
+
 ## 2.0.0 (2018-09-05)
 
 ### Breaking Change

From 0a08388f8d744dc2688181d870829484b3467de0 Mon Sep 17 00:00:00 2001
From: Daniel Bachhuber <daniel@bachhuber.co>
Date: Sun, 21 Oct 2018 08:20:43 -0700
Subject: [PATCH 17/21] Fetch as many attachments as we can, even if its not
 all of them

---
 packages/edit-post/src/hooks/components/media-upload/index.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/edit-post/src/hooks/components/media-upload/index.js b/packages/edit-post/src/hooks/components/media-upload/index.js
index 0e22b6cd5286ec..f950d34d628eee 100644
--- a/packages/edit-post/src/hooks/components/media-upload/index.js
+++ b/packages/edit-post/src/hooks/components/media-upload/index.js
@@ -68,6 +68,7 @@ const getAttachmentsCollection = ( ids ) => {
 		order: 'ASC',
 		orderby: 'post__in',
 		post__in: ids,
+		per_page: 100,
 		query: true,
 		type: 'image',
 	} );

From 1ce1f2b922de8f3e3c4e574acb32b6d8bedc60d7 Mon Sep 17 00:00:00 2001
From: Daniel Bachhuber <daniel@bachhuber.co>
Date: Sun, 21 Oct 2018 08:22:11 -0700
Subject: [PATCH 18/21] Remove `per_page=-1` support shim in REST API

---
 lib/rest-api.php                          | 148 ----------------------
 phpunit/class-gutenberg-rest-api-test.php |  38 +-----
 2 files changed, 3 insertions(+), 183 deletions(-)

diff --git a/lib/rest-api.php b/lib/rest-api.php
index 7506f45484ee79..35f4af5c52e77e 100644
--- a/lib/rest-api.php
+++ b/lib/rest-api.php
@@ -290,158 +290,10 @@ function gutenberg_register_post_prepare_functions( $post_type ) {
 	add_filter( "rest_prepare_{$post_type}", 'gutenberg_add_permalink_template_to_posts', 10, 3 );
 	add_filter( "rest_prepare_{$post_type}", 'gutenberg_add_block_format_to_post_content', 10, 3 );
 	add_filter( "rest_prepare_{$post_type}", 'gutenberg_add_target_schema_to_links', 10, 3 );
-	add_filter( "rest_{$post_type}_collection_params", 'gutenberg_filter_post_collection_parameters', 10, 2 );
-	add_filter( "rest_{$post_type}_query", 'gutenberg_filter_post_query_arguments', 10, 2 );
 	return $post_type;
 }
 add_filter( 'registered_post_type', 'gutenberg_register_post_prepare_functions' );
 
-/**
- * Whenever a taxonomy is registered, ensure we're hooked into its WP REST API response.
- *
- * @param string $taxonomy The newly registered taxonomy.
- */
-function gutenberg_register_taxonomy_prepare_functions( $taxonomy ) {
-	add_filter( "rest_{$taxonomy}_collection_params", 'gutenberg_filter_term_collection_parameters', 10, 2 );
-	add_filter( "rest_{$taxonomy}_query", 'gutenberg_filter_term_query_arguments', 10, 2 );
-}
-add_filter( 'registered_taxonomy', 'gutenberg_register_taxonomy_prepare_functions' );
-
-/**
- * Handle any necessary checks early.
- *
- * @param WP_HTTP_Response $response Result to send to the client. Usually a WP_REST_Response.
- * @param WP_REST_Server   $handler  ResponseHandler instance (usually WP_REST_Server).
- * @param WP_REST_Request  $request  Request used to generate the response.
- */
-function gutenberg_handle_early_callback_checks( $response, $handler, $request ) {
-	if ( 0 === strpos( $request->get_route(), '/wp/v2/' ) ) {
-		$can_unbounded_query = false;
-		$types               = get_post_types( array( 'show_in_rest' => true ), 'objects' );
-		foreach ( $types as $type ) {
-			if ( current_user_can( $type->cap->edit_posts ) ) {
-				$can_unbounded_query = true;
-			}
-		}
-		if ( $request['per_page'] < 0 ) {
-			if ( ! $can_unbounded_query ) {
-				return new WP_Error( 'rest_forbidden_per_page', __( 'Sorry, you are not allowed to make unbounded queries.', 'gutenberg' ), array( 'status' => rest_authorization_required_code() ) );
-			}
-		}
-	}
-	return $response;
-}
-add_filter( 'rest_request_before_callbacks', 'gutenberg_handle_early_callback_checks', 10, 3 );
-
-/**
- * Include additional query parameters on the posts query endpoint.
- *
- * @see https://core.trac.wordpress.org/ticket/43998
- *
- * @param array        $query_params JSON Schema-formatted collection parameters.
- * @param WP_Post_Type $post_type    Post type object being accessed.
- * @return array
- */
-function gutenberg_filter_post_collection_parameters( $query_params, $post_type ) {
-	if (
-		isset( $query_params['per_page'] ) &&
-		( $post_type->hierarchical || 'wp_block' === $post_type->name )
-	) {
-		// Change from '1' to '-1', which means unlimited.
-		$query_params['per_page']['minimum'] = -1;
-		// Default sanitize callback is 'absint', which won't work in our case.
-		$query_params['per_page']['sanitize_callback'] = 'rest_sanitize_request_arg';
-	}
-	return $query_params;
-}
-
-/**
- * Filter post collection query parameters to include specific behavior.
- *
- * @see https://core.trac.wordpress.org/ticket/43998
- *
- * @param array           $prepared_args Array of arguments for WP_Query.
- * @param WP_REST_Request $request       The current request.
- * @return array
- */
-function gutenberg_filter_post_query_arguments( $prepared_args, $request ) {
-	if (
-		is_post_type_hierarchical( $prepared_args['post_type'] ) ||
-		'wp_block' === $prepared_args['post_type']
-	) {
-		// Avoid triggering 'rest_post_invalid_page_number' error
-		// which will need to be addressed in https://core.trac.wordpress.org/ticket/43998.
-		if ( -1 === $prepared_args['posts_per_page'] ) {
-			$prepared_args['posts_per_page'] = 100000;
-		}
-	}
-	return $prepared_args;
-}
-
-/**
- * Include additional query parameters on the terms query endpoint.
- *
- * @see https://core.trac.wordpress.org/ticket/43998
- *
- * @param array  $query_params JSON Schema-formatted collection parameters.
- * @param object $taxonomy     Taxonomy being accessed.
- * @return array
- */
-function gutenberg_filter_term_collection_parameters( $query_params, $taxonomy ) {
-	if ( $taxonomy->show_in_rest
-		&& ( false === $taxonomy->rest_controller_class
-			|| 'WP_REST_Terms_Controller' === $taxonomy->rest_controller_class )
-		&& isset( $query_params['per_page'] ) ) {
-		// Change from '1' to '-1', which means unlimited.
-		$query_params['per_page']['minimum'] = -1;
-		// Default sanitize callback is 'absint', which won't work in our case.
-		$query_params['per_page']['sanitize_callback'] = 'rest_sanitize_request_arg';
-	}
-	return $query_params;
-}
-
-/**
- * Filter term collection query parameters to include specific behavior.
- *
- * @see https://core.trac.wordpress.org/ticket/43998
- *
- * @param array           $prepared_args Array of arguments for WP_Term_Query.
- * @param WP_REST_Request $request       The current request.
- * @return array
- */
-function gutenberg_filter_term_query_arguments( $prepared_args, $request ) {
-	// Can't check the actual taxonomy here because it's not
-	// passed through in $prepared_args (or the filter generally).
-	if ( 0 === strpos( $request->get_route(), '/wp/v2/' ) ) {
-		if ( -1 === $prepared_args['number'] ) {
-			// This should be unset( $prepared_args['number'] )
-			// but WP_REST_Terms Controller needs to be updated to support
-			// unbounded queries.
-			// Will be addressed in https://core.trac.wordpress.org/ticket/43998.
-			$prepared_args['number'] = 100000;
-		}
-	}
-	return $prepared_args;
-}
-
-/**
- * Include additional query parameters on the user query endpoint.
- *
- * @see https://core.trac.wordpress.org/ticket/43998
- *
- * @param array $query_params JSON Schema-formatted collection parameters.
- * @return array
- */
-function gutenberg_filter_user_collection_parameters( $query_params ) {
-	if ( isset( $query_params['per_page'] ) ) {
-		// Change from '1' to '-1', which means unlimited.
-		$query_params['per_page']['minimum'] = -1;
-		// Default sanitize callback is 'absint', which won't work in our case.
-		$query_params['per_page']['sanitize_callback'] = 'rest_sanitize_request_arg';
-	}
-	return $query_params;
-}
-add_filter( 'rest_user_collection_params', 'gutenberg_filter_user_collection_parameters' );
 
 /**
  * Silence PHP Warnings and Errors in JSON requests
diff --git a/phpunit/class-gutenberg-rest-api-test.php b/phpunit/class-gutenberg-rest-api-test.php
index 6dc323d6179bd7..293dc7fed3526c 100644
--- a/phpunit/class-gutenberg-rest-api-test.php
+++ b/phpunit/class-gutenberg-rest-api-test.php
@@ -381,17 +381,7 @@ public function test_get_items_unbounded_per_page() {
 		$request = new WP_REST_Request( 'GET', '/wp/v2/users' );
 		$request->set_param( 'per_page', '-1' );
 		$response = rest_get_server()->dispatch( $request );
-		$this->assertEquals( 200, $response->get_status() );
-	}
-
-	public function test_get_items_unbounded_per_page_unauthorized() {
-		wp_set_current_user( $this->subscriber );
-		$request = new WP_REST_Request( 'GET', '/wp/v2/users' );
-		$request->set_param( 'per_page', '-1' );
-		$response = rest_get_server()->dispatch( $request );
-		$this->assertEquals( 403, $response->get_status() );
-		$data = $response->get_data();
-		$this->assertEquals( 'rest_forbidden_per_page', $data['code'] );
+		$this->assertEquals( 400, $response->get_status() );
 	}
 
 	public function test_get_categories_unbounded_per_page() {
@@ -400,18 +390,7 @@ public function test_get_categories_unbounded_per_page() {
 		$request = new WP_REST_Request( 'GET', '/wp/v2/categories' );
 		$request->set_param( 'per_page', '-1' );
 		$response = rest_get_server()->dispatch( $request );
-		$this->assertEquals( 200, $response->get_status() );
-	}
-
-	public function test_get_categories_unbounded_per_page_unauthorized() {
-		wp_set_current_user( $this->subscriber );
-		$this->factory->category->create();
-		$request = new WP_REST_Request( 'GET', '/wp/v2/categories' );
-		$request->set_param( 'per_page', '-1' );
-		$response = rest_get_server()->dispatch( $request );
-		$this->assertEquals( 403, $response->get_status() );
-		$data = $response->get_data();
-		$this->assertEquals( 'rest_forbidden_per_page', $data['code'] );
+		$this->assertEquals( 400, $response->get_status() );
 	}
 
 	public function test_get_pages_unbounded_per_page() {
@@ -420,18 +399,7 @@ public function test_get_pages_unbounded_per_page() {
 		$request = new WP_REST_Request( 'GET', '/wp/v2/pages' );
 		$request->set_param( 'per_page', '-1' );
 		$response = rest_get_server()->dispatch( $request );
-		$this->assertEquals( 200, $response->get_status() );
-	}
-
-	public function test_get_pages_unbounded_per_page_unauthorized() {
-		wp_set_current_user( $this->subscriber );
-		$this->factory->post->create( array( 'post_type' => 'page' ) );
-		$request = new WP_REST_Request( 'GET', '/wp/v2/pages' );
-		$request->set_param( 'per_page', '-1' );
-		$response = rest_get_server()->dispatch( $request );
-		$this->assertEquals( 403, $response->get_status() );
-		$data = $response->get_data();
-		$this->assertEquals( 'rest_forbidden_per_page', $data['code'] );
+		$this->assertEquals( 400, $response->get_status() );
 	}
 
 	public function test_get_post_links_predecessor_version() {

From 93eeecc79e9ace3dc0c70f42d4a621a8d39a032f Mon Sep 17 00:00:00 2001
From: Daniel Bachhuber <daniel@bachhuber.co>
Date: Sun, 21 Oct 2018 09:00:45 -0700
Subject: [PATCH 19/21] Ensure the next page of results is actually fetched

---
 packages/api-fetch/src/middlewares/fetch-all-middleware.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 5bc17b5413d326..8cc2f9b603f66b 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -1,3 +1,8 @@
+/**
+ * Internal dependencies
+ */
+import apiFetch from '../';
+
 /**
  * WordPress dependencies
  */
@@ -75,7 +80,7 @@ const fetchAllMiddleware = async ( options, next ) => {
 	// Iteratively fetch all remaining pages until no "next" header is found.
 	let mergedResults = [].concat( results );
 	while ( nextPage ) {
-		const nextResponse = await next( {
+		const nextResponse = await apiFetch( {
 			...options,
 			// Ensure the URL for the next page is used instead of any provided path.
 			path: undefined,

From 08e8ca89c0c7520e1bdc3e4e7d9701c8bd0381a1 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 17:13:51 +0100
Subject: [PATCH 20/21] Tweak the middleware chain to avoid mutations

---
 packages/api-fetch/src/index.js                        | 10 ++++++----
 .../api-fetch/src/middlewares/fetch-all-middleware.js  |  7 +------
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/packages/api-fetch/src/index.js b/packages/api-fetch/src/index.js
index 4f6b3ce202645a..b028fef611e4b9 100644
--- a/packages/api-fetch/src/index.js
+++ b/packages/api-fetch/src/index.js
@@ -110,13 +110,15 @@ function apiFetch( options ) {
 		httpV1Middleware,
 		namespaceEndpointMiddleware,
 		...middlewares,
-	];
-	const next = ( nextOptions ) => {
-		const nextMiddleware = steps.pop();
+	].reverse();
+
+	const runMiddleware = ( index ) => ( nextOptions ) => {
+		const nextMiddleware = steps[ index ];
+		const next = runMiddleware( index + 1 );
 		return nextMiddleware( nextOptions, next );
 	};
 
-	return next( options );
+	return runMiddleware( 0 )( options );
 }
 
 apiFetch.use = registerMiddleware;
diff --git a/packages/api-fetch/src/middlewares/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
index 8cc2f9b603f66b..5bc17b5413d326 100644
--- a/packages/api-fetch/src/middlewares/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/fetch-all-middleware.js
@@ -1,8 +1,3 @@
-/**
- * Internal dependencies
- */
-import apiFetch from '../';
-
 /**
  * WordPress dependencies
  */
@@ -80,7 +75,7 @@ const fetchAllMiddleware = async ( options, next ) => {
 	// Iteratively fetch all remaining pages until no "next" header is found.
 	let mergedResults = [].concat( results );
 	while ( nextPage ) {
-		const nextResponse = await apiFetch( {
+		const nextResponse = await next( {
 			...options,
 			// Ensure the URL for the next page is used instead of any provided path.
 			path: undefined,

From 562250dd5fe32a9b0a5e3df8767a578a71dc476b Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Sun, 21 Oct 2018 17:25:47 +0100
Subject: [PATCH 21/21] Testing fetching consequential pages

---
 .../middlewares/test/fetch-all-middleware.js  | 25 ++++++++++++++-----
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js b/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js
index 930a7d7da970cc..c002790ead45c3 100644
--- a/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js
+++ b/packages/api-fetch/src/middlewares/test/fetch-all-middleware.js
@@ -17,22 +17,35 @@ describe( 'Fetch All Middleware', async () => {
 
 	it( 'should paginate the request', async () => {
 		expect.hasAssertions();
-		const originalOptions = { path: '/posts?per_page=-1' };
+		const originalOptions = { url: '/posts?per_page=-1' };
+		let counter = 1;
 		const next = ( options ) => {
-			expect( options.path ).toBe( '/posts?per_page=100' );
-			return Promise.resolve( {
+			if ( counter === 1 ) {
+				expect( options.url ).toBe( '/posts?per_page=100' );
+			} else {
+				expect( options.url ).toBe( '/posts?per_page=100&page=2' );
+			}
+			const response = Promise.resolve( {
 				status: 200,
 				headers: {
 					get() {
-						return '';
+						return options.url === '/posts?per_page=100' ?
+							'</posts?per_page=100&page=2>; rel="next"' :
+							'';
 					},
 				},
 				json() {
-					return Promise.resolve( { message: 'ok' } );
+					return Promise.resolve( [ 'item' ] );
 				},
 			} );
+
+			counter++;
+
+			return response;
 		};
 
-		await fetchAllMiddleware( originalOptions, next );
+		const result = await fetchAllMiddleware( originalOptions, next );
+
+		expect( result ).toEqual( [ 'item', 'item' ] );
 	} );
 } );