Build a Python Weibo Monitor: Simulate Login and Fetch Posts

0x00 Preface

After weeks of struggling with character‑encoding issues in a Weibo monitoring project, a new mobile API (https://m.weibo.cn/) was discovered that meets the requirements.

0x01 Analysis

Direct access to the API triggers a 302 redirect to a login page, so a simulated login is required. Packet analysis shows that a correct username and password return HTTP 200 with a JSON retcode of 20000000, and no captcha is needed.

After logging in, the user’s homepage (e.g., https://m.weibo.cn/u/3023940914) loads two XHR requests:

https://m.weibo.cn/api/container/getIndex?type=uid&value=3023940914&containerid=1005053023940914

https://m.weibo.cn/api/container/getIndex?type=uid&value=3023940914&containerid=1076033023940914

The first URL can be accessed by adding type and value parameters, while the containerid for the second request is obtained from the first response.

The second request returns a JSON where each post appears in the cards list; each card’s mblog array contains the post text, images, source, and timestamp. The card_type field indicates the post type (text, image, video, etc.), with text and image posts sharing card_type 9.

Initially the monitor focuses on text and image posts.

0x02 Development

Login simulation is performed with requests.session() . The following code snippets illustrate the process:

After a successful login, the first API URL is constructed with the user ID, and the containerid is retrieved to request the posts JSON.

All fetched post IDs are stored; subsequent polls compare new IDs to detect newly published posts.

The entire logic is encapsulated in a Python class (full source shown in the images below) and hosted on GitHub: https://github.com/naiquann/WBMonitor .

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0x03 Test

Running the script requires filling in login credentials and the target user ID. A heartbeat request is sent every three seconds to check for new posts; the interval can be adjusted for production use.

When a new post appears, the monitor triggers an email notification.

All set – the Weibo monitor is now operational.