It is assumed the reader is familiar with bencoding, as described in the BitTorrent protocol specification at http://www.bittorrent.org/protocol.html Dictionary keys used below will be enclosed in quotation marks, these are used for clarity and are not part of the actual key. The IPC protocol is used to allow processes to control or retrieve information from Transmission frontend, such as transmission-daemon, or the GTK+ or Mac OS X frontends. This communication is done over a unix-domain socket file such as ~/.transmission/daemon/socket. In this document the Transmission frontend will be referred to as the server and the process connecting to it as the client. Once a client connects to the server's socket, messages may be exchanged until either end closes the connection. Messages contain an 32-bit payload length, encoded as 8 bytes of ASCII hexadecimal, followed by the payload. Upper, lower, or mixed case for the length are all acceptable and must be handled correctly. Payload lengths greater than 2^31 - 8 (ie: 2147483640 decimal, 7FFFFFF8 hex) are not allowed. Bencoded messages will additionally be shown in the following format for better readability: str - "this is a string" num - 38795 list - ("wheeee", 435, "writing docs is boring") dict - {"name": "Josh", "beverage": "coffee", "quantity": "too damn much" } For version 1, the message payload is a bencoded dictionary, the valid keys and value formats for which are described below. Multiple keys may be used in one message. An example version 1 message: 0000000Ed4:porti51413ee {"port": 51413} For version 2 the message payload is a bencoded list containing a message id string followed by a bencoded value, the format of which is the same for version 1. The value may be followed by an optional bencoded integer, this is a message tag and is described in more detail below. An example version 2 message: 0000001El12:get-info-alll4:hashee ("get-info-all", ("hash")) The same message with a tag: 00000021l12:get-info-alll4:hashei5ee ("get-info-all", ("hash"), 5) Once the connection is made both the client and server must send a version 1 style message (ie: the payload is a dictionary and may not contain a tag) with the dictionary key "version" and a value formatted as described below. The version should be the first but not necessarily only key in the dictionary. Any other keys should be ignored and not processed as messages. Neither the client nor the server should wait to receive a version message before sending one, it must be sent immediately. No other messages should be sent until the version is received. The version value should be a bencoded dictionary containing two keys, "max" and "min". These are the minimum and maximum supported protocol versions, respectively. Communication will take place using the highest protocol version supported by both the client and the server, and is not possible at all if there is no common version. A client may receive a version value that is an integer instead of a dictionary with "min" and "max" keys. This deprecated version format indicates the only version supported by the server. The version dictionary may optionally contain a key "label". This is a human-readable name for the software, it is not machine-readable and neither servers nor clients should attempt to parse it. An example message containing minimum and maximum versions 1 and 2: 0000001Dd7:versiond3:mini1e3:maxi2eee {"version": {"min": 1, "max": 2}} Tagged messages, only supported in version 2, allow a client to tag a message with a positive non-zero integer. The server is then required to send a response to the message even if none would normally be required, and to tag the response with the same integer. When the server receives a tagged message it must send exactly one message back with the same tag. The client is allowed to use the same tag for multiple messages, even if a response to the first is not received before the second it sent. If a tagged message does not normally require a response then a "succeeded", "failed", "not-supported" or "bad-format" message will be sent back. An example tagged message and response: 00000010l5:startli8eei15ee ("start", (8), 15) 00000011l8:succeeded0:i15ee ("succeeded", "", 15) Some example sessions, including version handshake, are found at the end of this file. Dictionary keys are encoded in UTF-8 and case sensitive. Any character except a NUL (0x00) is valid. A server or client need not support every possible key and should silently ignore any that it does not understand. If a reference to a boolean is seen, it should be taken to mean an integer with a value of 0 representing false, 1 representing true, and any other value undefined. Individual torrents are identified by a unique integer. This integer is only valid for the current connection and may be invalid or refer to another torrent in a future connection. If a torrent is closed it's ID will never be reused to refer to another torrent for at least the duration of the connection. Negative integers or 0 are not valid IDs. A list of keys and the format of their values follows. Also listed is the minimum protocol version that the key may be used with. Key: "addfiles" Version: 1 Format: list of strings Replies: "succeeded", "failed", "not-supported", "bad-format", "info" Example: 8:addfilesl21:/torrents/foo.torrent20:/home/me/bar.torrente "addfiles", ("/torrents/foo.torrent", /home/me/bar.torrent") Details: Each string is the absolute path to a torrent metainfo file for the server to add. Note that whether or not the torrent metainfo file is copied (allowing the original to be moved or deleted safely) is implementation dependent and may not currently be known or changed with this protocol. Key: "addfile-detailed" Version: 2 Format: dict Replies: "succeeded", "failed", "not-supported", "bad-format", "info" Example: 16:addfile-detailedd4:file19:/tor/wooble.torrente "addfile-detailed", {"file": "/tor/wooble.torrent"} Details: Dictionary containing information about a torrent for the server to add. Valid keys include: "file" string, filename of torrent metainfo file "data" string, contents of a torrent metainfo file "directory" string, directory for data files for the torrent "autostart" boolean, start the torrent automatically Either "file" or "data" is required, but both are not allowed. Key: "automap" Version: 2 Format: boolean Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 7:automapi1e "automap", 1 Details: Enable (1) or disable (0) automatic port mapping on the server. Key: "autostart" Version: 2 Format: boolean Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 9:autostarti0e "autostart", 0 Details: Enable (1) or disable (0) automatic starting of new torrents added via "addfiles" or "addfiles-detailed" messages. Key: "bad-format" Version: 2 Format: value is ignored Replies: N/A Example: 10:bad-format0: "bad-format", "" Details: Sent in response to a tagged message which was structured incorrectly. For example, an "autostart" message with a string value might cause this message to be returned. Key: "directory" Version: 2 Format: string Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 9:directory21:/home/roger/downloads "directory", "/home/roger/downloads" Details: Set the default directory used for any torrents added in the future. Key: "downlimit" Version: 2 Format: int Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 9:downlimiti100e "downlimit", 100 Details: Set the server's download limit in kilobytes per second. Negative values are interpreted as no limit. Key: "encryption" Version: 2 Format: string Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 10:encryption8:required "encryption", "required" Details: Set the encryption mode for peer connections. Valid values are "required", "preferred" and "plaintext". Key: "failed" Version: 2 Format: string Replies: N/A Example: 6:failed17:permission denied "failed", "permission denied" Details: Sent in response to a tagged message to indicate failure. Key: "get-automap" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "automap" Example: 11:get-automap0: "get-automap", "" Details: Requests that an "automap" message be sent back. Key: "get-autostart" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "autostart" Example: 13:get-autostart0: "get-autostart", "" Details: Requests that an "autostart" message be sent back. Key: "get-directory" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "directory" Example: 13:get-directory0: "get-directory", "" Details: Requests that an "directory" message be sent back. Key: "get-downlimit" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "downlimit" Example: 13:get-downlimit0: "get-downlimit", "" Details: Requests that a "downlimit" message be sent back. Key: "get-encryption" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "encryption" Example: 14:get-encryption0: "get-encryption", "" Details: Requests that an "encryption" message be sent back. Key: "get-info" Version: 2 Format: dict with keys "id" and "type" for lists of ints and strings Replies: "failed", "not-supported", "bad-format", "info" Example: 8:get-infod2:idli4ei7ei2ee4:typel4:hash4:nameee "get-info", {"id": (4, 7, 2), "type": ("hash", "name")} Details: Requests that the server send back an "info" message with info on all the torrent IDs in "id". The "type" key requests what info will be returned. See below for valid values to use here. Since the torrent ID is always included in an "info" message an empty or missing "type" key will cause only the ID to be returned. An "info" message will always be sent back, even if it is empty. Key: "get-info-all" Version: 2 Format: list of strings Replies: "failed", "not-supported", "bad-format", "info" Example: 12:get-info-alll4:hash4:namee "get-info-all", ("hash", "name") Details: Same as "get-info" message with all torrent IDs specified. Key: "get-pex" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "pex" Example: 7:get-pex0: "get-pex", "" Details: Requests that a "pex" message be sent back. Key: "get-port" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "port" Example: 8:get-port0: "get-port", "" Details: Requests that a "port" message be sent back. Key: "get-status" Version: 2 Format: dict with keys "id" and "type" for lists of ints and strings Replies: "failed", "not-supported", "bad-format", "status" Example: 10:get-statusd2:idli4ei7ei2ee4:typel5:state9:completedee "get-status", {"id": (4, 7, 4), "type": ("state", "completed")} Details: Same as "get-info" message except status type strings are used instead and the server sends back a "status" message. Key: "get-status-all" Version: 2 Format: list of strings Replies: "failed", "not-supported", "bad-format", "status" Example: 14:get-status-alll5:state9:completede "get-status-all", ("state", "completed") Details: Same as "get-status" message with all torrent IDs specified. Key: "get-supported" Version: 2 Format: list of strings Replies: "failed", "not-supported", "bad-format", "supported" Example: 13:get-supportedl6:lookup8:get-port16:addfile-detailede "get-supported", ("lookup", "get-port", "addfile-detailed") Details: Request that a "supported" message be returned with whichever of the given message keys are supported. Key: "get-uplimit" Version: 2 Format: value is ignored Replies: "failed", "not-supported", "bad-format", "uplimit" Example: 11:get-uplimit0: "get-uplimit", "" Details: Requests that an "uplimit" message be sent back. Key: "lookup" Version: 2 Format: list of strings Replies: "failed", "not-supported", "bad-format", "info" Example: 6:lookupl40:0f16ea6965ee5133ea4dbb1e7f516e9fcf3d899ee "lookup", ("0f16ea6965ee5133ea4dbb1e7f516e9fcf3d899e") Details: Request that the server send back an "info" message with "id" and "hash" keys for any torrents with the given hashes. Key: "info" Version: 2 Format: list of dictionaries Replies: N/A Example: 4:infold2:idi3e4:name3:fooed2:idi9e4:name3:baree "info", ({"id": 4, "name": "foo"}, {"id": 9, "name": "bar"}) Details: A list containing information for several torrents. The dictionaries always contain at least an "id" key with the integer ID for the torrent, other possible values are listed below. Key: "noop" Version: 2 Format: value is ignored Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 4:noop0: "noop", "" Details: This does nothing but keep the connection alive. With a tag it may be used as a ping. Key: "not-supported" Version: 2 Format: value is ignored Replies: N/A Example: 13:not-supported0: "not-supported", "" Details: Sent in response to a tagged message to indicated that the message was not supported. Key: "pex" Version: 2 Format: boolean Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 3:pexi0e "pex", 0 Details: Enables or disables peer exchange. Key: "port" Version: 2 Format: int between 0 and 65535 Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 4:porti51413e "port", 51413 Details: Change the port the server uses to listen for incoming peer connections. Key: "encryption" Version: 2 Format: string Example: 10:encryption9:preferred "encryption", "preferred" Details: Returns thestring is one of: "required", "preferred", "tolerated" Key: "quit" Version: 1 Format: value is ignored Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 4:quit0: "quit", "" Details: Cause the server to quit. Note that the connection might be closed without a response being sent. Key: "remove" Version: 2 Format: list of torrent ID ints Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 5:removeli3ei8ei6ee "remove", (3, 8, 6) Details: Stop and remove the specified torrents. Note that whether or not the downloaded data or the original torrent files will be removed is implementation dependent and may not currently be known or changed with this protocol. If a saved copy of the torrent file has been made then it will always be deleted. Key: "remove-all" Version: 2 Format: value is ignored Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 10:remove-all0: "remove-all", "" Details: Like "remove" with all torrent IDs specified. Key: "start" Version: 2 Format: list of torrent ID ints Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 5:startli3ei8ei6ee "start", (3, 8, 6) Details: List of torrent IDs to start. Key: "start-all" Version: 2 Format: value is ignored Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 9:start-all0: "start-all", "" Details: Start all torrents. Key: "status" Version: 2 Format: list of dictionaries Replies: N/A Example: 4:infold2:idi3e5:state7:seedinged2:idi9e5:state6:pausedee "info", ({"id": 3, "state": "seeding"}, {"id": 9, "state" : "paused"}) Details: Same as "info" message except status type keys are used. Key: "stop" Version: 2 Format: list of torrent ID ints Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 4:stopli3ei8ei6ee "stop", (3, 8, 6) Details: List of torrent IDs to stop. Key: "stop-all" Version: 2 Format: value is ignored Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 8:stop-all0: "stop-all", "" Details: Stop all torrents. Key: "succeeded" Version: 2 Format: value is ignored Replies: N/A Example: 8:succeeded0: "succeeded", "" Details: This is used to indicate that a tagged message was processed successfully. Key: "supported" Version: 2 Format: list of strings Replies: N/A Example: 9:supportedl8:get-port6:lookupe "supported", ("get-port", "lookup") Details: Sent in response to a "get-supported" message, indicates that the given messages ate supported. Key: "uplimit" Version: 2 Format: int Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 7:uplimiti20e "uplimit", 20 Details: Set the server's upload limit in kilobytes per second. Negative values are interpreted as no limit. Key: "verify" Version: 2 Format: list of torrent ID ints Replies: "succeeded", "failed", "not-supported", "bad-format" Example: 6:verifyli3ei8ei6ee "verify", (3, 8, 6) Details: List of torrent IDs to stop. Info types for "get-info" and "info" messages. The only type for which support is mandatory is "id". "id" integer, torrent's ID for this connection "hash" SHA-1 info hash as a 40-char hex string "name" string, torrent name "path" string, path to .torrent file "saved" boolean, true if a copy of this torrent was saved "private" boolean, true if the torrent is private "trackers" a list of lists of dictionaries containing tracker info: "address" string, hostname or ip address of tracker "port" integer, port for tracker "announce" string, announce url on tracker "scrape" string, scrape url on tracker, may be absent "comment" string, comment from torrent file "creator" string, creator of torrent file "date" integer, date of torrent creation (unix time_t format) "size" integer, total size of all files in bytes "files" list of dictionaries for the files in this torrent: "name" string, name of file "size" integer, size of file in bytes Status types for "get-status" and "status" messages. The only type for which support is mandatory is "id". "completed" integer, bytes of data downloaded and verified "download-speed" integer, download speed in bytes per second "download-total" integer, total bytes downloaded so far "error" string, one of the following: "assert" something happened that shouldn't "io-parent" missing parent directory "io-permissions" filesystem permission error "io-space" not enough free space in filesystem "io-resource" insufficient resources "io-other" other filesystem i/o error "tracker-error" tracker returned error message "tracker-warning" tracker returned warning message "other" other error zero-length or missing string indicates no error "error-message" string, printable error message "eta" integer, estimated seconds until downloading is finished "id" integer, torrent's ID for this connection "peers-downloading" integer, peers downloading from us "peers-from" dict with the following int keys, peer connection sources: "incoming" peers connected to our listening port "tracker" peers discovered from tracker "cache" peers retrieved from on-disk cache "pex" peers discovered via peer exchange "peers-total" integer, total connected peers "peers-uploading" integer, peers uploading to us "running" boolean, false if torrent is stopped or stopping "state" string, one of the following: "checking" performing hash check on file data "downloading" downloading file data "seeding" seeding file data to peers "stopping" contacting tracker to send 'stopped' event "paused" torrent is not active "waiting to checking" torrent is queued for hash check. yes, this it really is called that. "swarm-speed" integer, swarm speed in bytes per second "tracker" dict with the following keys, current active tracker "address" string, hostname or ip address of tracker "port" integer, port for tracker "announce" string, tracker announce url "scrape" string, tracker scrape url, may be absent "scrape-completed" integer, total completed peers as reported by tracker "scrape-leechers" integer, current leechers as reported by tracker "scrape-seeders" integer, current, seeders as reported by tracker "upload-speed" integer, upload speed in bytes per second "upload-total" integer, total bytes uploaded so far Examples: Data from the client to the server is prefixed with >>> and from server to client with <<<. These prefixes and newlines are added for clarity, they are not actually sent over the socket. Quit the server. Note that this is a version 1 client and so version 1 messages are used. >>> 0000001Dd7:versiond3:mini1e3:maxi1eee {"version", {"min": 1, "max": 1"}} <<< 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} >>> 0000000Bd4:quit0:e {"quit": ""} Pause all torrents and disable automapping. Note the server happens to have sent it's version before the client. The value for the stop-all message here is 5:fnord instead of 0: as used above, since the value is unused anything is allowed. <<< 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} >>> 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} >>> 0000000El8:stop-all5:fnorde ("stop-all", "fnord") Change upload and download limits with tagged responses. >>> 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} <<< 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} >>> 00000017l9:downlimiti100ei47el ("downlimit", 100, 47) >>> 00000017l9:uplimiti20ei48ee ("uplimit", 20, 48) <<< 00000014l8:succeeded0:i47ee ("succeeded", "", 47) <<< 00000014l8:succeeded0:i48ee (succeeded"", "", 48) Retrieve the upload and download limits. Note that the server has returned the responses in a different order than the requests were sent. The server is allowed to do this, a client should use tags if this is a concern. >>> 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} <<< 0000001Dd7:versiond3:mini1e3:maxi2eee {"version", {"min": 1, "max": 2"}} >>> 00000015l13:get-downlimiti0ee00000013l13:get-uplimiti0ee ("get-downlimit", 0) ("get-uplimit", 0) <<< 0000000Fl9:uplimiti20ee00000012l9:downlimiti100ee ("uplimit", 20) ("downlimit", 100)