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Diffstat (limited to 'Documentation/technical/api-credentials.txt')
| -rw-r--r-- | Documentation/technical/api-credentials.txt | 68 |
1 files changed, 62 insertions, 6 deletions
diff --git a/Documentation/technical/api-credentials.txt b/Documentation/technical/api-credentials.txt index 21ca6a2..adb6f0c 100644 --- a/Documentation/technical/api-credentials.txt +++ b/Documentation/technical/api-credentials.txt @@ -6,8 +6,52 @@ password credentials from the user (even though credentials in the wider world can take many forms, in this document the word "credential" always refers to a username and password pair). +This document describes two interfaces: the C API that the credential +subsystem provides to the rest of git, and the protocol that git uses to +communicate with system-specific "credential helpers". If you are +writing git code that wants to look up or prompt for credentials, see +the section "C API" below. If you want to write your own helper, see +the section on "Credential Helpers" below. + +Typical setup +------------- + +------------ ++-----------------------+ +| git code (C) |--- to server requiring ---> +| | authentication +|.......................| +| C credential API |--- prompt ---> User ++-----------------------+ + ^ | + | pipe | + | v ++-----------------------+ +| git credential helper | ++-----------------------+ +------------ + +The git code (typically a remote-helper) will call the C API to obtain +credential data like a login/password pair (credential_fill). The +API will itself call a remote helper (e.g. "git credential-cache" or +"git credential-store") that may retrieve credential data from a +store. If the credential helper cannot find the information, the C API +will prompt the user. Then, the caller of the API takes care of +contacting the server, and does the actual authentication. + +C API +----- + +The credential C API is meant to be called by git code which needs to +acquire or store a credential. It is centered around an object +representing a single credential and provides three basic operations: +fill (acquire credentials by calling helpers and/or prompting the user), +approve (mark a credential as successfully used so that it can be stored +for later use), and reject (mark a credential as unsuccessful so that it +can be erased from any persistent storage). + Data Structures ---------------- +~~~~~~~~~~~~~~~ `struct credential`:: @@ -21,14 +65,17 @@ Data Structures The `helpers` member of the struct is a `string_list` of helpers. Each string specifies an external helper which will be run, in order, to either acquire or store credentials. See the section on credential -helpers below. +helpers below. This list is filled-in by the API functions +according to the corresponding configuration variables before +consulting helpers, so there usually is no need for a caller to +modify the helpers field at all. + This struct should always be initialized with `CREDENTIAL_INIT` or `credential_init`. Functions ---------- +~~~~~~~~~ `credential_init`:: @@ -72,7 +119,7 @@ Functions Parse a URL into broken-down credential fields. Example -------- +~~~~~~~ The example below shows how the functions of the credential API could be used to login to a fictitious "foo" service on a remote host: @@ -135,8 +182,10 @@ credentials from and to long-term storage (where "long-term" is simply longer than a single git process; e.g., credentials may be stored in-memory for a few minutes, or indefinitely on disk). -Each helper is specified by a single string. The string is transformed -by git into a command to be executed using these rules: +Each helper is specified by a single string in the configuration +variable `credential.helper` (and others, see linkgit:git-config[1]). +The string is transformed by git into a command to be executed using +these rules: 1. If the helper string begins with "!", it is considered a shell snippet, and everything after the "!" becomes the command. @@ -243,3 +292,10 @@ request. If a helper receives any other operation, it should silently ignore the request. This leaves room for future operations to be added (older helpers will just ignore the new requests). + +See also +-------- + +linkgit:gitcredentials[7] + +linkgit:git-config[5] (See configuration variables `credential.*`) |