From 08ae33635a031cb3c96792a3dc4423b1f79f4082 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=87=89=E5=87=89?= <xyqfer@gmail.com>
Date: Mon, 11 Mar 2019 11:02:35 +0800
Subject: [PATCH] Add: tg channel photo (#1714)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- 目前只处理了非私有频道的图片(不包括图片文件)显示
- Closes #903
---
 lib/routes/telegram/channel.js | 113 ++++++++++++++++++++-------------
 1 file changed, 70 insertions(+), 43 deletions(-)

diff --git a/lib/routes/telegram/channel.js b/lib/routes/telegram/channel.js
index bb62a5ff21..6b41e3b655 100644
--- a/lib/routes/telegram/channel.js
+++ b/lib/routes/telegram/channel.js
@@ -1,6 +1,7 @@
 const axios = require('../../utils/axios');
 const config = require('../../config');
 const logger = require('../../utils/logger');
+const cheerio = require('cheerio');
 
 let botName = '';
 axios({
@@ -18,6 +19,22 @@ module.exports = async (ctx) => {
     const username = ctx.params.username;
     const cacheDays = 30;
     const cacheLength = 5;
+    const fomatPhoto = async (link) => {
+        const imgList = [];
+        const { data } = await axios.get(link + '?embed=1&single=1');
+        const $ = cheerio.load(data);
+
+        $('.tgme_widget_message_photo_wrap').each(function() {
+            const bg = $(this).css('background-image');
+            imgList.push(bg.match(/url\('(.+)'\)/)[1]);
+        });
+        return imgList.reduce((acc, img) => {
+            if (img) {
+                acc += `<img referrerpolicy="no-referrer" src="${img}">`;
+            }
+            return acc;
+        }, '');
+    };
 
     let response = await axios({
         method: 'get',
@@ -41,54 +58,64 @@ module.exports = async (ctx) => {
         ctx.cache.set(`RSSHubTelegramChannelName${username}`, data[0].channel_post.chat.title, cacheDays * 24 * 60 * 60);
 
         // cache post
-        post = data.map((item) => {
-            item = item.channel_post;
-            let text = item.text || item.caption || '';
-            const media = ['photo', 'audio', 'document', 'game', 'sticker', 'video', 'voice', 'contact', 'location', 'venue'];
-            media.forEach((me) => {
-                if (item[me]) {
-                    text += ` [${me}]`;
-                }
-            });
-
-            let html = text;
-
-            if (item.entities) {
-                const enter = [];
-                item.entities.forEach((entity) => {
-                    switch (entity.type) {
-                        case 'text_link':
-                            enter.push([entity.offset, `<a href="${entity.url}">`], [entity.offset + entity.length, '</a>']);
-                            break;
-                        case 'bold':
-                            enter.push([entity.offset, '<b>'], [entity.offset + entity.length, '</b>']);
-                            break;
-                        case 'hashtag':
-                        case 'italic':
-                            enter.push([entity.offset, '<i>'], [entity.offset + entity.length, '</i>']);
-                            break;
+        post = await Promise.all(
+            data.map(async (item) => {
+                item = item.channel_post;
+                let text = item.text || item.caption || '';
+                let html = text;
+                const link = `https://t.me/${username}/${item.message_id}`;
+                const media = ['photo', 'audio', 'document', 'game', 'sticker', 'video', 'voice', 'contact', 'location', 'venue'];
+                // https://css-tricks.com/why-using-reduce-to-sequentially-resolve-promises-works/
+                await media.reduce(async (acc, me) => {
+                    if (item[me]) {
+                        if (item.chat.username && me === 'photo') {
+                            // 暂时只处理非私有频道的图片
+                            const photos = await fomatPhoto(link);
+                            html += ` ${photos}`;
+                        }
+                        text += ` [${me}]`;
                     }
-                });
-                enter.sort((a, b) => a[0] - b[0]);
-                if (enter.length) {
-                    html = text.slice(0, enter[0][0]);
-                    enter.forEach((en, index) => {
-                        if (index !== enter.length - 1) {
-                            html += enter[index][1] + text.slice(enter[index][0], enter[index + 1][0]);
-                        } else {
-                            html += enter[index][1] + text.slice(enter[index][0]);
+                    return acc;
+                }, Promise.resolve());
+
+                if (item.entities) {
+                    const enter = [];
+                    item.entities.forEach((entity) => {
+                        switch (entity.type) {
+                            case 'text_link':
+                                enter.push([entity.offset, `<a href="${entity.url}">`], [entity.offset + entity.length, '</a>']);
+                                break;
+                            case 'bold':
+                                enter.push([entity.offset, '<b>'], [entity.offset + entity.length, '</b>']);
+                                break;
+                            case 'hashtag':
+                            case 'italic':
+                                enter.push([entity.offset, '<i>'], [entity.offset + entity.length, '</i>']);
+                                break;
                         }
                     });
+                    enter.sort((a, b) => a[0] - b[0]);
+                    if (enter.length) {
+                        html = text.slice(0, enter[0][0]);
+                        enter.forEach((en, index) => {
+                            if (index !== enter.length - 1) {
+                                html += enter[index][1] + text.slice(enter[index][0], enter[index + 1][0]);
+                            } else {
+                                html += enter[index][1] + text.slice(enter[index][0]);
+                            }
+                        });
+                    }
                 }
-            }
 
-            return {
-                title: text,
-                description: html,
-                pubDate: new Date(item.date * 1000).toUTCString(),
-                link: `https://t.me/${username}/${item.message_id}`,
-            };
-        });
+                return Promise.resolve({
+                    title: text,
+                    description: html,
+                    pubDate: new Date(item.date * 1000).toUTCString(),
+                    link,
+                });
+            })
+        );
+
         if (post.length >= cacheLength) {
             ctx.cache.set(`RSSHubTelegramChannelPost${username}`, post.slice(0, cacheLength), cacheDays * 24 * 60 * 60);
         } else {