APPP – a Python Implementation of APJP

Version: 0.1.3
4.4 MiB

Important! Encryption in APJP and APPP (and by extension other proxy software that make use of these) is incorrectly implemented. Do NOT use these with vital private info, or at the very least use these over HTTPS.

Latest version is 0.1.3



APJP is a proxy (originally) written in PHP and JAVA. It uses PHP/Python/JAVA application deployed on remote server as server-side, JAVA application installed on local computer/mobile device as client-side, and ARC4 encryption in-between.

APPP is a Python implementation of APJP. Currently, APPP only offers client-side application, but it should work with any APJP server-side application regardless of the language used by the latter.


There have been only JAVA-based client-side applications for Linux, Windows and Android. Some people may be troubled by the following issues:

  • JAVA is not available in their OS of choice, or not freely available, or not freely available under a ‘free’ license, or they are simply not happy about the dismaying JAVA vulnerabilities;
  • Memory footprint of JAVA applications precludes their use in embedded devices, such as routers;
  • It’s cumbersome to configure and run multiple JAVA-based APJP clients simultaneously.

APPP was intended to address these issues. Over time, new functionalities have also been added.


For instructions on deployment of server-side APJP applications, please visit APJP wiki.

APPP requires Python 2.6 and above, and pyOpenSSL. These are available by default on most desktop and server distros of Linux. For Windows, either install Python and pyOpenSSL manually or use the precompiled Win32 application in the package linked below. APPP is compatible with Python3.

Download the APPP python script and packaged Win32 application here, define an APPP server in APPP.ini to match server-side deployment, and from within the appp python folder type ‘/path/to/python servername’ or for Win32 application, type ‘appp servername’ to start.

To disable certificate warnings prompted by browsers when visiting https sites through APPP, import ‘APPP.pem’ (generated after the first run) in appp folder into your browser as Trusted Root Certification Authorities (CA).

Tips and Tricks

Security versus Performance

APJP/APPP encrypts entire proxied traffic using the key shared by the client and server. As long as the key is not compromised (do NOT use a key that might be known to someone else!), it is very, very, very difficult for the proxied traffic to be decrypted if the connection is being eavesdropped on or under man-in-the-middle attacks. But that is not to say decryption is not possible. If this possibility really concerns you, one way to make the connection slightly more secure and decryption more difficult is to run APJP server over https to add an extra layer of protection.

Two considerations need to be addressed before going the https way. First, additional encryption and decryption introduced by https will cause extra CPU, memory and network usage, possibly resulting in slower performance. Second, a valid certificate is required for APJP over https to make actual sense security-wise. APPP checks certificate of APJP server running https against Mozilla’s root ca bundle and by default, refuses to connect if certificate is invalid. This behavior could be overridden in the config file, but the appropriate solution if a self-signed certificate need to be used is to add the self-generated root ca to the cacert.pem file.

Transparent Proxy

Not all internet-connecting applications support proxies, especially on mobile and embedded devices. The only way around this is to use DNS or firewall tricks to redirect the traffic to a transparent proxy server. APPP works as both normal proxy and transparent proxy, without any special setting. APPP could also work as a dedicated transparent https proxy if TRANSPARENT_HTTPS is set to yes. Here ‘dedicated’ means only normal https requests could be handled and all other types of requests will fail. Fortunately, it is most trivial to run multiple APPP proxies simultaneously in a single process to handle all types of http/https requests. Unfortunately, visiting https sites through transparent proxy will prompt invalid certificate warnings. To minimize the inconveniences, specify all frequently visited domains in the TRANSPARENT_HTTPS_DOMAINS setting.


Append ‘-d’ option when starting APPP to get detailed debugging messages. Post the messages here if still at a loss.


20130310: 0.1.3

Allow specifying alternative config file using ‘-c’ option;

Handle normal http requests (as transparent http proxy);

Add support for APJP server running over https;

Handle normal https requests (as transparent https proxy only).

20120519: 0.1.2

Add TIMEOUT configuration; better timeout handling.

20120519: 0.1.1

Fix compatibility with APJP_REMOTE_PHP > 0.8.2.

20120515: 0.1

Initial release.



48 Responses to APPP – a Python Implementation of APJP

  1. Phil says:

    Hi, Farter, I have open on the hotfile link you gave, but only win32 app, no python script, I want to deploy it on my iOS device, so can you plz upload it again, thanks!

  2. Eric says:

    With APJP java version, all servers are listening to single port and APJP banlance among all the servers. for APPP, single server listens to a port. Is it possible to have banlance implementation in your great appp?

    • farter says:

      Yes it is possible, but I’m not gonna implement it.

      Having such a setup means your source IP, as website/servers see it, is constantly changing.

      This creates all sorts of problems.

      • Eric says:

        this will happen only with multi servers. but people who need unchanged ip can config only one server in the config file. even you can give a parameter to enable user config what sites they need unchanged ip and others thru banlanced servers.

        • farter says:

          I can not understand why anybody would want to use contantly changing IP. If you really want it, simply use batch or shell to restart APPP with different server every now and then.

  3. Pentium says:

    How to solve this problem: ERROR: Exception encountered forwarding request: u’/_URL

    • farter says:

      Well, that description does not give any details at all. But my wild guess is you messed up the INI file.

      • Pentium says:

        Actually I run APPP on my router and try to use it for some website.
        I add this line “address=/″ to dnsmasq configure file.
        I also create a redirecting rule “iptables -t nat -I PREROUTING -i br0 -p tcp -d –dport 80 -j DNAT –to-destination″.
        The listen address and port is set like this “″.
        Then this error occurs. But when I use extensions like “switchsharp” in chrome to set proxy like this “″, it works.

  4. master says:

    What are the requirements for this script ?
    Whether there is a script to be installed on the host , and this requirement is to show up or not ?
    Free hosting that allows you to install it ?

  5. yourfans says:

    And APJP has been updated to 1.0.0. There should be something news in the latest version. Can you update the APPP to fix up some bugs and achieve the new function too?
    Thank you again and again ^_^

    • farter says:

      There is not much that is ‘new’ regarding the protocol, just some changes to implementation details, which are almost unnoticeble to users.

  6. yourfans says:

    There is a function in APJP’s properties file like this:
    Because mainland China can not open the appspot site directly,this property is useful to work on GAE.

    I try to set up the APPP.ini file like this:
    (or CUSTOM_HEADER1=Host:
    (or CUSTOM_HEADER1=’’)
    (or CUSTOM_HEADER1=’Host:’)
    However,none is work. Even do not pass the HTTP_TEST_SITE/HTTPS_TEST_SITE.

    How can APPP to achieve the same functionality?

    • farter says:


      I’ve tested that using IP in HTTP(S)_URL and hostname in CUSTOM_HEADER works with shared hosting. So you can try using google IP instead of You can also try using instead of the https.

      • yourfans says:

        It works. Thank you.

        • yourfans says:

          Because of the improvement of China GFW,above method requesting over HTTP has died no matter which IP.(request reset)
          APJP is still alive as it can use HTTPS.
          So,hope to implement the HTTPS request.

          • farter says:

            As I mentioned earlier, APJP/APPP over https wastes server resources unnecessarily. The easiest solution would be not using Google appspot, which is not meant to be used for such purposes anyway, and use other hosting/vps/server services not blocked by the wall.

  7. Liberty says:


    • farter says:

      Hi, you can enable debugging, try to visit the problematic files or images, and see the log for clues.

      If you are using the script, you can use ‘pythonw’ instead of ‘python’ to execute the script. No cmd console will be shown, but you will miss all the logs.

  8. @twfcc says:

    this is the error message from JB iPad2 iOS 511 with python 2.7.1 & pyOpenSSL installed.

    “Address already in use” message is appeared no matter I change
    Any idea? Thanks

    07:00:53 APPP[MainThread] INFO: Attempting to run all APPP servers defined in APPP.ini
    07:00:53 APPP[MainThread] INFO: Processing [EXAMPLE] configurations
    07:00:53 APPP[MainThread] INFO: Processing [EXAMPLE-PROXY] configurations
    07:00:53 APPP[MainThread] INFO: Checking APPP certificates…
    07:00:53 APPP[MainThread] INFO: APPP certificates OK.
    07:00:53 APPP[EXAMPLE-PROXY] INFO: Listening on
    07:00:53 APPP[EXAMPLE-PROXY-TEST] INFO: Testing APPP connectivity to
    07:00:53 APPP[EXAMPLE] ERROR: Binding to failed: [Errno 48] Address already in use
    07:00:53 APPP[EXAMPLE-PROXY-TEST] INFO: Testing APPP connectivity to
    07:00:53 APPP[EXAMPLE-PROXY-805195776] INFO: Received connection from
    07:00:53 APPP[EXAMPLE-PROXY-18354176] INFO: Received connection from
    07:00:54 APPP[EXAMPLE-PROXY-805195776] ERROR: Exception encountered processing request from [Errno 54] Connection reset by peer
    07:00:54 APPP[EXAMPLE-PROXY-18354176] ERROR: Exception encountered processing request from [Errno 54] Connection reset by peer
    07:00:54 APPP[EXAMPLE-PROXY-TEST] ERROR: APPP connectivity test to failed: no correctly formatted response header received.
    07:00:54 APPP[EXAMPLE-PROXY-TEST] ERROR: APPP connectivity test to failed: no correctly formatted response header received.

    • farter says:

      ‘Address already in use’ because you are running multiple APPP servers but failed to set them to bind to different ports.

      In your log, EXAMPLE-PROXY was the first to be run and bind successfully ’07:00:53 APPP[EXAMPLE-PROXY] INFO: Listening on’

      • littlewater says:

        The same error as twfcc.
        with enabled log-debug, I found the error may caused by nothing-data return in “client_buffer” at line 306(ver 0.1.2)
        And I tried using wireshark to trace the error As following :
        (where is my local IP)

        No. Time Source Destination Protocol Length Info
        18 5.084760000 TCP 66 9688 > https [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=4 SACK_PERM=1
        19 5.086134000 TCP 66 9689 > https [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=4 SACK_PERM=1
        20 5.410802000 TCP 66 https > 9688 [SYN, ACK] Seq=0 Ack=1 Win=5840 Len=0 MSS=1452 SACK_PERM=1 WS=256
        21 5.410892000 TCP 54 9688 > https [ACK] Seq=1 Ack=1 Win=66792 Len=0
        22 5.412722000 SSL 258 Continuation Data
        23 5.412977000 TCP 66 https > 9689 [SYN, ACK] Seq=0 Ack=1 Win=5840 Len=0 MSS=1452 SACK_PERM=1 WS=256
        24 5.413022000 TCP 54 9689 > https [ACK] Seq=1 Ack=1 Win=66792 Len=0
        25 5.414534000 SSL 259 Continuation Data
        28 5.738494000 TCP 60 https > 9688 [ACK] Seq=1 Ack=205 Win=6912 Len=0
        29 5.738547000 SSL 114 Continuation Data
        30 5.739062000 TCP 60 https > 9688 [FIN, ACK] Seq=1 Ack=205 Win=6912 Len=0
        31 5.739095000 TCP 54 9688 > https [ACK] Seq=265 Ack=2 Win=66792 Len=0
        32 5.739566000 TCP 60 https > 9688 [RST, ACK] Seq=2 Ack=205 Win=6912 Len=0
        33 5.745162000 TCP 60 https > 9689 [ACK] Seq=1 Ack=206 Win=6912 Len=0
        34 5.745194000 SSL 114 Continuation Data
        35 5.745719000 TCP 60 https > 9689 [FIN, ACK] Seq=1 Ack=206 Win=6912 Len=0
        36 5.745745000 TCP 54 9689 > https [ACK] Seq=266 Ack=2 Win=66792 Len=0
        37 5.746231000 TCP 60 https > 9689 [RST, ACK] Seq=2 Ack=206 Win=6912 Len=0
        41 6.067161000 TCP 60 https > 9688 [RST] Seq=2 Win=0 Len=0
        42 6.073064000 TCP 60 https > 9689 [RST] Seq=1 Win=0 Len=0
        43 6.073477000 TCP 60 https > 9689 [RST] Seq=2 Win=0 Len=0

        the server and client without any hello exists, I thought it may failed during SSL validation??

        • littlewater says:

          well, I thought I got the key …
          I guess APPP won’t support SSL but should use http:// instead of default APJP https:// connection ….

          after changed this, the logger reported OK for everything, and even this post MAY post by APPP, but I doubt this method safety ….

          But compared with large costs JAVA, this is really memory saved for python though ….

          • farter says:

            No, appp over https is not implemented, as it seems to be a little bit redundant (encryption within encryption) and resource-wasteful (encryption overhead).

  9. niming says:

    system: centos6.2
    problem:outside the path,run ‘python /path/to/ -a’ will not work, showing not found the appp.ini file.similar project goagent do not have the problem.

    • farter says:

      Maybe next version. Or you could just use ‘cd /path/to/ && python -a’.

      • niming says:

        i’ve created a sh file with this code:
        cd /path/to/
        python -a
        and set to ‘startup application’.every time logined,it will run automatically.

  10. @twfcc says:

    great jobs, APJP now can running on JailBreak iOS device, thanks!

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