switch to node-fetch (#2587)

* switch to node-fetch

* remove useless var declaration

* remove method uppercasing

* rework concurrency

* Revert "rework concurrency"

This reverts commit ef6aa2697e.

* fix headers

src/rest/APIRequest.js

@@ -1,7 +1,8 @@
 const querystring = require('querystring');
-const snekfetch = require('snekfetch');
+const FormData = require('form-data');
 const https = require('https');
 const { browser, UserAgent } = require('../util/Constants');
+const fetch = require('node-fetch');
 
 if (https.Agent) var agent = new https.Agent({ keepAlive: true });
 
@@ -17,24 +18,34 @@ class APIRequest {
     this.path = `${path}${queryString ? `?${queryString}` : ''}`;
   }
 
-  gen() {
+  make() {
     const API = this.options.versioned === false ? this.client.options.http.api :
       `${this.client.options.http.api}/v${this.client.options.http.version}`;
+    const url = API + this.path;
+    let headers = {};
 
-    const request = snekfetch[this.method](`${API}${this.path}`, { agent });
-
-    if (this.options.auth !== false) request.set('Authorization', this.rest.getAuth());
-    if (this.options.reason) request.set('X-Audit-Log-Reason', encodeURIComponent(this.options.reason));
-    if (!browser) request.set('User-Agent', UserAgent);
-    if (this.options.headers) request.set(this.options.headers);
+    if (this.options.auth !== false) headers.Authorization = this.rest.getAuth();
+    if (this.options.reason) headers['X-Audit-Log-Reason'] = encodeURIComponent(this.options.reason);
+    if (!browser) headers['User-Agent'] = UserAgent;
+    if (this.options.headers) headers = Object.assign(headers, this.options.headers);
 
+    let body;
     if (this.options.files) {
-      for (const file of this.options.files) if (file && file.file) request.attach(file.name, file.file, file.name);
-      if (typeof this.options.data !== 'undefined') request.attach('payload_json', JSON.stringify(this.options.data));
-    } else if (typeof this.options.data !== 'undefined') {
-      request.send(this.options.data);
+      body = new FormData();
+      for (const file of this.options.files) if (file && file.file) body.append(file.name, file.file, file.name);
+      if (typeof this.options.data !== 'undefined') body.append('payload_json', JSON.stringify(this.options.data));
+      if (!browser) headers = Object.assign(headers, body.getHeaders());
+    } else if (this.options.data != null) { // eslint-disable-line eqeqeq
+      body = JSON.stringify(this.options.data);
+      headers['Content-Type'] = 'application/json';
     }
-    return request;
+
+    return fetch(url, {
+      method: this.method,
+      headers,
+      agent,
+      body,
+    });
   }
 }
 

src/rest/handlers/RequestHandler.js

@@ -68,34 +68,37 @@ class RequestHandler {
           resolve();
         }
       };
-      item.request.gen().end((err, res) => {
+      item.request.make().then(res => {
         if (res && res.headers) {
-          if (res.headers['x-ratelimit-global']) this.manager.globallyRateLimited = true;
-          this.limit = Number(res.headers['x-ratelimit-limit']);
-          this.resetTime = Date.now() + Number(res.headers['retry-after']);
-          this.remaining = Number(res.headers['x-ratelimit-remaining']);
+          if (res.headers.get('x-ratelimit-global')) this.manager.globallyRateLimited = true;
+          this.limit = Number(res.headers.get('x-ratelimit-limit') || Infinity);
+          this.resetTime = Number(res.headers.get('x-ratelimit-reset') || 0);
+          this.remaining = Number(res.headers.get('x-ratelimit-remaining') || 1);
         }
-        if (err) {
-          if (err.status === 429) {
-            this.queue.unshift(item);
-            finish(Number(res.headers['retry-after']) + this.client.options.restTimeOffset);
-          } else if (err.status >= 500 && err.status < 600) {
-            if (item.retried) {
-              item.reject(err);
-              finish();
-            } else {
-              item.retried = true;
-              this.queue.unshift(item);
-              finish(1e3 + this.client.options.restTimeOffset);
-            }
-          } else {
-            item.reject(err.status >= 400 && err.status < 500 ?
-              new DiscordAPIError(res.request.path, res.body, res.request.method) : err);
+
+        if (res.ok) {
+          res.json().then(item.resolve, item.reject);
+          finish();
+          return;
+        }
+
+        if (res.status === 429) {
+          this.queue.unshift(item);
+          finish(Number(res.headers.get('retry-after')) + this.client.options.restTimeOffset);
+        } else if (res.status >= 500 && res.status < 600) {
+          if (item.retried) {
+            item.reject(res);
             finish();
+          } else {
+            item.retried = true;
+            this.queue.unshift(item);
+            finish(1e3 + this.client.options.restTimeOffset);
           }
         } else {
-          const data = res && res.body ? res.body : {};
-          item.resolve(data);
+          res.json().then(data => {
+            item.reject(res.status >= 400 && res.status < 500 ?
+              new DiscordAPIError(item.path, data, item.method) : res);
+          }, item.reject);
           finish();
         }
       });

src/util/DataResolver.js

@@ -1,6 +1,6 @@
 const path = require('path');
 const fs = require('fs');
-const snekfetch = require('snekfetch');
+const fetch = require('node-fetch');
 const Util = require('../util/Util');
 const { Error: DiscordError, TypeError } = require('../errors');
 const { browser } = require('../util/Constants');
@@ -83,13 +83,13 @@ class DataResolver {
    * @returns {Promise<Buffer>}
    */
   static resolveFile(resource) {
-    if (resource instanceof Buffer) return Promise.resolve(resource);
+    if (!browser && resource instanceof Buffer) return Promise.resolve(resource);
     if (browser && resource instanceof ArrayBuffer) return Promise.resolve(Util.convertToBuffer(resource));
 
     if (typeof resource === 'string') {
       if (/^https?:\/\//.test(resource)) {
-        return snekfetch.get(resource).then(res => res.body instanceof Buffer ? res.body : Buffer.from(res.text));
-      } else {
+        return fetch(resource).then(res => browser ? res.blob() : res.buffer());
+      } else if (!browser) {
         return new Promise((resolve, reject) => {
           const file = browser ? resource : path.resolve(resource);
           fs.stat(file, (err, stats) => {

src/util/Util.js

@@ -1,6 +1,6 @@
-const snekfetch = require('snekfetch');
 const Collection = require('./Collection');
 const { Colors, DefaultOptions, Endpoints } = require('./Constants');
+const fetch = require('node-fetch');
 const { Error: DiscordError, RangeError, TypeError } = require('../errors');
 const has = (o, k) => Object.prototype.hasOwnProperty.call(o, k);
 const splitPathRe = /^(\/?|)([\s\S]*?)((?:\.{1,2}|[^/]+?|)(\.[^./]*|))(?:[/]*)$/;
@@ -90,15 +90,14 @@ class Util {
    * @returns {Promise<number>} The recommended number of shards
    */
   static fetchRecommendedShards(token, guildsPerShard = 1000) {
-    return new Promise((resolve, reject) => {
-      if (!token) throw new DiscordError('TOKEN_MISSING');
-      snekfetch.get(`${DefaultOptions.http.api}/v${DefaultOptions.http.version}${Endpoints.botGateway}`)
-        .set('Authorization', `Bot ${token.replace(/^Bot\s*/i, '')}`)
-        .end((err, res) => {
-          if (err) reject(err);
-          resolve(res.body.shards * (1000 / guildsPerShard));
-        });
-    });
+    if (!token) throw new DiscordError('TOKEN_MISSING');
+    return fetch(`${DefaultOptions.http.api}/v${DefaultOptions.http.version}${Endpoints.botGateway}`, {
+      method: 'GET',
+      headers: { Authorization: `Bot ${token.replace(/^Bot\s*/i, '')}` },
+    }).then(res => {
+      if (res.ok) return res.json();
+      throw res;
+    }).then(data => data.shards * (1000 / guildsPerShard));
   }
 
   /**