This document covers using the OAuth2 protocol to access GitLab.
This document covers using the [OAuth2](https://oauth.net/2/) protocol to allow other services access Gitlab resources on user's behalf.
If you want GitLab to be an OAuth authentication service provider to sign into other services please see the [Oauth2 provider documentation](../integration/oauth_provider.md).
If you want GitLab to be an OAuth authentication service provider to sign into other services please see the [OAuth2 provider](../integration/oauth_provider.md)
documentation.
OAuth2 is a protocol that enables us to authenticate a user without requiring them to give their password to a third-party.
This functionality is based on [doorkeeper gem](https://github.com/doorkeeper-gem/doorkeeper).
This functionality is based on [doorkeeper gem](https://github.com/doorkeeper-gem/doorkeeper)
## Supported OAuth2 Flows
## Web Application Flow
Gitlab currently supports following authorization flows:
This is the most common type of flow and is used by server-side clients that wish to access GitLab on a user's behalf.
**Web Application Flow* - Most secure and common type of flow, designed for the applications with secure server-side.
**Implicit Flow* - This flow is designed for user-agent only apps (e.g. single page web application running on GitLab Pages).
**Resource Owner Password Credentials Flow* - To be used **only** for securely hosted, first-party services.
>**Note:**
Please refer to [OAuth RFC](https://tools.ietf.org/html/rfc6749) to find out in details how all those flows work and pick the right one for your use case.
This flow **should not** be used for client-side clients as you would leak your `client_secret`. Client-side clients should use the Implicit Grant (which is currently unsupported).
For more detailed information, check out the [RFC spec](http://tools.ietf.org/html/rfc6749#section-4.1)
Both *web application* and *implicit* flows require `application` to be registered first via `/profile/applications` page
in your user's account. During registration, by enabling proper scopes you can limit the range of resources which the `application` can access. Upon creation
you'll obtain `application` credentials: _Application ID_ and _Client Secret_ - **keep them secure**.
In the following sections you will be introduced to the three steps needed for this flow.
>**Important:** OAuth specification advises sending `state` parameter with each request to `/oauth/authorize`. We highly recommended to send a unique
value with each request and validate it against the one in redirect request. This is important to prevent [CSRF attacks]. The `state` param really should
have been a requirement in the standard!
### 1. Registering the client
In the following sections you will find detailed instructions on how to obtain authorization with each flow.
First, you should create an application (`/profile/applications`) in your user's account.
### Web Application Flow
Each application gets a unique App ID and App Secret parameters.
>**Note:**
Check [RFC spec](http://tools.ietf.org/html/rfc6749#section-4.1) for a detailed flow description
**You should not share/leak your App ID or App Secret.**
### 2. Requesting authorization
#### 1. Requesting authorization code
To request the authorization code, you should redirect the user to the `/oauth/authorize` endpoint:
To request the authorization code, you should redirect the user to the `/oauth/authorize` endpoint with following GET parameters:
This will ask the user to approve the applications access to their account and then redirect back to the `REDIRECT_URI` you provided.
This will ask the user to approve the applications access to their account and then redirect back to the `REDIRECT_URI` you provided. The redirect will
include the GET `code` parameter, for example:
The redirect will include the GET `code` parameter, for example:
You should then use the `code` to request an access token.
You should then use the `code` to request an access token.
>**Important:**
#### 2. Requesting access token
It is highly recommended that you send a `state` value with the request to `/oauth/authorize` and
validate that value is returned and matches in the redirect request.
This is important to prevent [CSRF attacks](http://www.oauthsecurity.com/#user-content-authorization-code-flow),
`state` really should have been a requirement in the standard!
### 3. Requesting the access token
Once you have the authorization code you can request an `access_token` using the code, to do that you can use any HTTP client. In the following example, we are using Ruby's `rest-client`:
Once you have the authorization code you can request an `access_token` using the code, to do that you can use any HTTP client. In the following example,
Check [RFC spec](http://tools.ietf.org/html/rfc6749#section-4.3) for a detailed flow description.
1. Starting in GitLab 8.11, the Resource Owner Password Credentials has been *disabled* for users with two-factor authentication turned on.
> **Deprecation notice:** Starting in GitLab 8.11, the Resource Owner Password Credentials has been *disabled* for users with two-factor authentication
2. These users can access the API using [personal access tokens] instead.
turned on. These users can access the API using [personal access tokens] instead.
---
In this flow, a token is requested in exchange for the resource owner credentials (username and password).
In this flow, a token is requested in exchange for the resource owner credentials (username and password).
The credentials should only be used when there is a high degree of trust between the resource owner and the client (e.g. the
The credentials should only be used when there is a high degree of trust between the resource owner and the client (e.g. the
...
@@ -101,12 +109,16 @@ client is part of the device operating system or a highly privileged application
...
@@ -101,12 +109,16 @@ client is part of the device operating system or a highly privileged application
available (such as an authorization code).
available (such as an authorization code).
>**Important:**
>**Important:**
Never store the users credentials and only use this grant type when your client is deployed to a trusted environment, in 99% of cases [personal access tokens] are a better choice.
Never store the users credentials and only use this grant type when your client is deployed to a trusted environment, in 99% of cases [personal access tokens]
are a better choice.
Even though this grant type requires direct client access to the resource owner credentials, the resource owner credentials are used
Even though this grant type requires direct client access to the resource owner credentials, the resource owner credentials are used
for a single request and are exchanged for an access token. This grant type can eliminate the need for the client to store the
for a single request and are exchanged for an access token. This grant type can eliminate the need for the client to store the
resource owner credentials for future use, by exchanging the credentials with a long-lived access token or refresh token.
resource owner credentials for future use, by exchanging the credentials with a long-lived access token or refresh token.
You can do POST request to `/oauth/token` with parameters: