mitmproxy Tutorial (MuMu 12 Automation)

Special Disclaimer

1. Scope: The following statements apply only to the "FGO Login Data Automation Capture Tool (including run.bat and fgo_cap.py)".
2. Server Support: This tool ONLY supports the Mainland China (CN) and Taiwan (TW) servers operated by bilibili. It DOES NOT support Japanese (JP), Korean (KR), or North American (NA) servers.
3. Ownership: This tool and its documentation do not represent the position of this site or the Chaldea Project team.
4. Author: This article was written by vx13.

[ Legal Statement and Authorization ]

• Project Independence: This script and related tools are independently developed third-party auxiliary tools. Their ownership does not belong to the official developers of "Fate/Grand Order," their affiliates, or the Chaldea Project team.
• Technical Background: The core logic, environment self-check process, and this documentation were designed and written with the assistance of AI (Artificial Intelligence).
• Copyright and Licensing: No copyright restrictions are placed on this tool. The developer welcomes and encourages any individual or organization to study, modify, secondary develop, extend features, and distribute or promote it within the community.
• Disclaimer: This tool is for technical exchange and learning purposes only, aimed at optimizing the user data management experience. The developer and the AI collaborator shall not be held liable for any direct or indirect consequences (such as account abnormalities, privacy leaks, etc.) resulting from the use of this tool. Users must comply with local laws, regulations, and game service agreements.
• Security Tip: The captured raw login data contains sensitive credentials. Please keep it secure and never share it with others.

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0. Tool Download

This is an all-in-one package with the engine (mitmdump) bundled, so no Python or mitmproxy installation is required.

• Download Link: Mirrored download

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1. Emulator Preparation (MuMu 12)

Please complete the following settings and restart the emulator, otherwise the script will be unable to perform low-level operations:

Setting	Path	Value
Root Permission	[Device Settings] - [Others]	On
System Disk Writable	[Device Settings] - [Disk]	Select "Writable System Disk"
ADB Debugging	[Device Settings] - [Others]	Select "Enable Local Connection"

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2. Operation and Capture Flow

1. Start Script: Double-click run.bat. Wait for the self-check to complete until you see [🚀] 正在监听....
2. Login to Game: Launch FGO in the emulator. Enter the game until you see the "Globe" screen or the "Event Announcement."
3. Auto-Finish: Once capture succeeds, the window shows [🎯] 捕获成功!; the script restores the proxy and exits, then run.bat waits for a key press — press any key to close. The data is now stored in your clipboard.

Notice: Manual Exit and Network Recovery

• Proper Exit: If you need to stop manually, press Ctrl + C in the window. Do not directly click the red [X] in the top-right corner.
• Network Fix: If the emulator cannot access the internet due to an abnormal shutdown, run run.bat again and press Ctrl + C to exit properly, or go to emulator [Wi-Fi Settings] and set [Proxy] to "None".

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3. Import to Chaldea

1. Open the Chaldea client.
2. Open the [Import] menu at the bottom-right of the home page -> [HTTPS Sniffing], click the import button at the top-right and choose [from Clipboard].

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4. Script Workflow

Step	Execution Logic
Cert Generation	Searches for the CA certificate in the user directory; if missing, silently launches mitmdump in the background to generate it.
ADB Search	Locates and calls the native adb.exe within the emulator's installation directory by retrieving the file path of the MuMuNxDevice process.
ADB Connection	Executes kill-server and start-server sequentially to reset services; establishes a connection via a 127.0.0.1:5555 handshake.
Cert Injection	Compares user directory certificates with emulator system certificates based on MD5 hashes; uploads and overwrites if the certificate is missing or hashes mismatch.
Proxy Configuration	Automatically resolves the active LAN IP of the host machine; injects proxy parameters into the emulator's global settings via the adb shell settings interface.
Capture Analysis	Matches specific interface suffixes (_key=toplogin); extracts the raw response body and writes it to the Windows clipboard via a system pipe.
Proxy Cleanup	Monitors for successful capture or Ctrl + C signals; resets the emulator's global proxy to off (:0) to restore the network environment.