Create url link (#1888)

* UrlLink.create(url) with OpenGraph (#1887)

* 0.29.10

* add open graph supported

* 0.29.11

package.json

 {
   "name": "wechaty",
-  "version": "0.29.9",
+  "version": "0.29.11",
   "description": "Wechaty is a Bot SDK for Wechat Personal Account",
   "main": "dist/src/index.js",
   "typings": "dist/src/index.d.ts",
@@ -87,6 +87,7 @@
     "in-gfw": "^1.2.0",
     "memory-card": "^0.6.9",
     "npm-programmatic": "0.0.12",
+    "open-graph": "^0.2.4",
     "opencollective": "^1.0.3",
     "opencollective-postinstall": "^2.0.2",
     "pkg-dir": "^4.0.0",
@@ -115,6 +116,7 @@
     "@types/glob": "^5.0.0p",
     "@types/mime": "^2.0.0",
     "@types/node": "^12.12.3",
+    "@types/open-graph": "^0.2.0",
     "@types/promise-retry": "^1.1.3",
     "@types/qr-image": "^3.2.1",
     "@types/raven": "^2.1.0",

src/helper-functions/impure/open-graph.ts

+import og from 'open-graph'
+
+export async function openGraph (url: string): Promise<og.Data> {
+  return new Promise((resolve, reject) => {
+    og(url, (err, meta) => {
+      if (err) {
+        reject(err)
+      } else {
+        resolve(meta)
+      }
+    })
+  })
+}

src/user/url-link.ts

+import Url from 'url'
+
 import {
   UrlLinkPayload,
 }                   from 'wechaty-puppet'
@@ -6,6 +8,10 @@ import {
   log,
 }               from '../config'
 
+import {
+  openGraph,
+}               from '../helper-functions/impure/open-graph'
+
 export class UrlLink {
 
   /**
@@ -16,11 +22,51 @@ export class UrlLink {
   public static async create (url: string): Promise<UrlLink> {
     log.verbose('UrlLink', 'create(%s)', url)
 
-    // TODO: get title/description/thumbnailUrl from url automatically
+    const meta = await openGraph(url)
+
+    let description: string | undefined
+    let imageUrl: string | undefined
+    let title: string
+
+    if (Array.isArray(meta.description)) {
+      description = meta.description[0]
+    } else if (meta.description) {
+      description = meta.description
+    }
+
+    if (meta.image) {
+      if (typeof meta.image === 'string') {
+        imageUrl = meta.image
+      } else if (Array.isArray(meta.image)) {
+        imageUrl = meta.image[0]
+      } else {
+        if (Array.isArray(meta.image.url)) {
+          imageUrl = meta.image.url[0]
+        } else if (meta.image.url) {
+          imageUrl = meta.image.url
+        }
+      }
+    }
+
+    if (Array.isArray(meta.title)) {
+      title = meta.title[0]
+    } else {
+      title = meta.title
+    }
+
+    if (!imageUrl || !description) {
+      throw new Error('imageUrl or description not found!')
+    }
+
+    if (!imageUrl.startsWith('http')) {
+      const resolvedUrl = new Url.URL(imageUrl, url)
+      imageUrl = resolvedUrl.toString()
+    }
+
     const payload: UrlLinkPayload = {
-      description  : 'todo',
-      thumbnailUrl : 'todo',
-      title        : 'todo',
+      description,
+      thumbnailUrl: imageUrl,
+      title,
       url,
     }