Add sendFile function (#562)

* sendFile

* Add default value to filename

* eslint

* (╯°□°）╯︵ ┻━┻

package.json

@@ -32,8 +32,8 @@
     "opusscript": "^0.0.1"
   },
   "devDependencies": {
-    "jsdoc-parse": "^1.2.7",
-    "fs-extra": "^0.30.0"
+    "fs-extra": "^0.30.0",
+    "jsdoc-parse": "^1.2.7"
   },
   "optionalDependencies": {
     "node-opus": "^0.1.13"

src/client/ClientDataResolver.js

@@ -1,3 +1,7 @@
+const path = require('path');
+const fs = require('fs');
+const request = require('superagent');
+
 const getStructure = name => require(`../structures/${name}`);
 
 const User = getStructure('User');
@@ -163,6 +167,41 @@ class ClientDataResolver {
 
     return String(data);
   }
+
+  /**
+   * Data that can be resolved to give a Buffer. This can be:
+   * * A Buffer
+   * * The path to a local file
+   * * An URL
+   * @typedef {String|Buffer} FileResolvable
+   */
+
+  /**
+   * Resolves a FileResolvable to a Buffer
+   * @param {FileResolvable} fileResolvable the file resolvable to resolve
+   * @returns {String|Buffer}
+   */
+  resolveFile(resource) {
+    if ($string(resource)) {
+      return new Promise((resolve, reject) => {
+        if (/^https?:\/\//.test(resource)) {
+          request.get(resource)
+          .set('Content-Type', 'blob')
+          .end((err, res) => err ? reject(err) : resolve(res.body));
+        } else {
+          const file = path.resolve(resource);
+          const stat = fs.statSync(file);
+          if (!stat.isFile()) {
+            return reject(new Error(`The file could not be found: ${file}`));
+          }
+
+          return resolve(fs.readFileSync(file));
+        }
+      });
+    }
+
+    return Promise.resolve(resource);
+  }
 }
 
 module.exports = ClientDataResolver;

src/client/rest/APIRequest.js

@@ -29,12 +29,14 @@ class APIRequest {
     if (this.auth) {
       apiRequest.set('authorization', this.getAuth());
     }
+    if (this.file && this.file.file) {
+      apiRequest.set('Content-Type', 'multipart/form-data');
+      apiRequest.attach('file', this.file.file, this.file.name);
+    }
     if (this.data) {
       apiRequest.send(this.data);
     }
-    if (this.file) {
-      apiRequest.attach('file', this.file.file, this.file.name);
-    }
+
     apiRequest.set('User-Agent', this.rest.userAgentManager.userAgent);
     return apiRequest;
   }

src/client/rest/RESTMethods.js

@@ -41,7 +41,7 @@ class RESTMethods {
     });
   }
 
-  sendMessage($channel, content, tts, nonce) {
+  sendMessage($channel, content, tts, nonce, file) {
     return new Promise((resolve, reject) => {
       const $this = this;
       let channel = $channel;
@@ -49,7 +49,7 @@ class RESTMethods {
       function req() {
         $this.rest.makeRequest('post', Constants.Endpoints.channelMessages(channel.id), true, {
           content, tts, nonce,
-        })
+        }, file)
         .then(data => resolve($this.rest.client.actions.MessageCreate.handle(data).m))
         .catch(reject);
       }

src/structures/DMChannel.js

@@ -47,6 +47,10 @@ class DMChannel extends Channel {
     return;
   }
 
+  sendFile() {
+    return;
+  }
+
   _cacheMessage() {
     return;
   }

src/structures/GroupDMChannel.js

@@ -124,6 +124,10 @@ class GroupDMChannel extends Channel {
     return;
   }
 
+  sendFile() {
+    return;
+  }
+
   _cacheMessage() {
     return;
   }

src/structures/GuildMember.js

@@ -222,6 +222,10 @@ class GuildMember {
   sendTTSMessage() {
     return;
   }
+
+  sendFile() {
+    return;
+  }
 }
 
 TextBasedChannel.applyToClass(GuildMember);

src/structures/TextChannel.js

@@ -32,6 +32,10 @@ class TextChannel extends GuildChannel {
     return;
   }
 
+  sendFile() {
+    return;
+  }
+
   _cacheMessage() {
     return;
   }

src/structures/User.js

@@ -122,6 +122,10 @@ class User {
   sendTTSMessage() {
     return;
   }
+
+  sendFile() {
+    return;
+  }
 }
 
 TextBasedChannel.applyToClass(User);

src/structures/interface/TextBasedChannel.js

@@ -68,7 +68,24 @@ class TextBasedChannel {
   sendTTSMessage(content, options = {}) {
     return this.client.rest.methods.sendMessage(this, content, true, options.nonce);
   }
-
+  /**
+   * Send a file to this channel
+   * @param {FileResolvable} attachment The file to send
+   * @param {String} [fileName="file.jpg"] The name and extension of the file
+   * @returns {Promise<Message>}
+   */
+  sendFile(attachment, fileName = 'file.jpg') {
+    return new Promise((resolve, reject) => {
+      this.client.resolver.resolveFile(attachment)
+      .then(file => {
+        this.client.rest.methods.sendMessage(this, undefined, false, undefined, {
+          file,
+          name: fileName,
+        }).then(resolve).catch(reject);
+      })
+      .catch(reject);
+    });
+  }
   /**
    * The parameters to pass in when requesting previous messages from a channel. `around`, `before` and
    * `after` are mutually exclusive. All the parameters are optional.
@@ -173,7 +190,7 @@ function applyProp(structure, prop) {
 }
 
 exports.applyToClass = (structure, full = false) => {
-  const props = ['sendMessage', 'sendTTSMessage'];
+  const props = ['sendMessage', 'sendTTSMessage', 'sendFile'];
   if (full) {
     props.push('_cacheMessage');
     props.push('getMessages');