feat: Support subscribe GitHub file commits (#2002)

* feat: Support subscribe github single file

* refact: Use GitHub API to crawl commits

* Use GitHub API to crawl commits
* Update document

* Add access_token for github file commits api

docs/programming.md

@@ -95,6 +95,21 @@ GitHub 官方也提供了一些 RSS:
 
 <Route name="仓库 Branches" author="max-arnold" example="/github/branches/DIYgod/RSSHub" path="/github/branches/:user/:repo" :paramsDesc="['用户名', '仓库名']"/>
 
+<Route name="文件 Commits" author="zengxs" example="/github/file/DIYgod/RSSHub/master/lib/router.js" path="/github/file/:user/:repo/:branch/:filepath+" :paramsDesc="['用户名', '仓库名', '分支名', '文件路径']">
+
+| 用户名   | 仓库名   | 分支名   | 文件路径        |
+| -------- | -------- | -------- | --------------- |
+| `DIYgod` | `RSSHub` | `master` | `lib/router.js` |
+
+> -   **分支名**中如果有 `/` 等特殊字符需使用 urlencode 进行编码，通常 `/` 需要被替换成 `%2f`
+> -   **文件路径**中如果有特殊字符同样需使用 urlencode 进行编码，但文件路径可以正常识别 `/` 字符
+> -   **文件路径**如果以 `.rss`, `.atom`, `.json` 结尾，需要将后缀中的 `.` 替换成 `%2e`
+>     > Reeder 订阅 `%2erss` 或类似后缀的时候会出错，此时再在路由后面加上 `.rss` 即可正常订阅
+>     >
+>     > 如： `https://rsshub.app/github/file/DIYgod/RSSHub/master/lib/router%2ejs` 替换成 `https://rsshub.app/github/file/DIYgod/RSSHub/master/lib/router%2ejs.rss` 即可
+
+</Route>
+
 <Route name="搜索结果" author="LogicJake" example="/github/search/RSSHub/bestmatch/desc" path="/github/search/:query/:sort?/:order?" :paramsDesc="['搜索关键词', '排序选项（默认为bestmatch）','排序顺序，desc和asc（默认desc降序）']"/>
 
 | 排序选项           | sort      |

lib/router.js

@@ -345,6 +345,7 @@ router.get('/github/user/followers/:user', require('./routes/github/follower'));
 router.get('/github/stars/:user/:repo', require('./routes/github/star'));
 router.get('/github/search/:query/:sort?/:order?', require('./routes/github/search'));
 router.get('/github/branches/:user/:repo', require('./routes/github/branches'));
+router.get('/github/file/:user/:repo/:branch/:filepath+', require('./routes/github/file'));
 
 // f-droid
 router.get('/fdroid/apprelease/:app', require('./routes/fdroid/apprelease'));

lib/routes/github/file.js

@@ -0,0 +1,47 @@
+const axios = require('../../utils/axios');
+const config = require('../../config');
+
+module.exports = async (ctx) => {
+    const user = ctx.params.user;
+    const repo = ctx.params.repo;
+    const branch = ctx.params.branch;
+    const filepath = ctx.params.filepath;
+
+    const fileUrl = `https://github.com/${user}/${repo}/commits/${branch}/${filepath}`;
+
+    const reqParams = {
+        sha: branch,
+        path: filepath,
+    };
+    if (config.github.access_token) {
+        reqParams.access_token = config.github.access_token;
+    }
+
+    const res = await axios.get(`https://api.github.com/repos/${user}/${repo}/commits`, {
+        params: reqParams,
+    });
+    const list = res.data;
+    const count = [];
+    for (let i = 0; i < Math.min(list.length, 10); i++) {
+        count.push(i);
+    }
+    const resultItems = await Promise.all(
+        count.map(async (i) => {
+            const each = list[i];
+            const item = {
+                title: each.commit.message.split('\n')[0],
+                description: `<pre>${each.commit.message}</pre>`,
+                link: each.html_url,
+                author: each.commit.author.name,
+                pubDate: new Date(each.commit.committer.date).toUTCString(),
+            };
+            return Promise.resolve(item);
+        })
+    );
+
+    ctx.state.data = {
+        title: `GitHub File - ${user}/${repo}/${branch}/${filepath}`,
+        link: fileUrl,
+        item: resultItems,
+    };
+};