# Authenticating via OAuth

PRAW supports the three types of applications that can be registered on Reddit. Those are:

- Web Applications
- Installed Applications
- Script Applications

Before you can use any one of these with PRAW, you must first register an application of the appropriate type on Reddit.

If your app does not require a user context, it is read only.

PRAW supports the flows that each of these applications can use. The following table defines which tables can use which flows:

Application Type | Script | Web | Installed
--- | --- | --- | ---
Default Flow | Password | Code
Alternative Flows | Code | Application Only (Client Credentials) | Implicit
Application Only (Client Credentials)
Application Only (Installed Client)

## Password Flow

Password Flow is the simplest type of authentication flow to work with because no callback process is involved in obtaining an `access_token`.

While password flow applications do not involve a redirect uri, Reddit still requires that you provide one when registering your script application – `http://localhost:8080` is a simple one to use.

In order to use a password flow application with PRAW you need four pieces of information:

client_id: | The client ID is the 14 character string listed just under “personal use script” for the desired developed application
client_secret: | The client secret is the 27 character string listed adjacent to `secret` for the application.
password: | The password for the Reddit account used to register the application.
username: | The username of the Reddit account used to register the application.

With this information authorizing as `username` using a password flow app is as simple as:

    reddit = praw.Reddit(client_id='SI8pN3DSbt0zor',
                         client_secret='xaxkj7HNh8kwg8e5t4m6KvSrbTI',
                         password='1guiwevlfo00esyy',
                         user_agent='testscript by /u/fakebot3',
                         username='fakebot3')

To verify that you are authenticated as the correct user run:

    print(reddit.user.me())

The output should contain the same name as you entered for `username`.

Note

If the following exception is raised, double check your credentials, and ensure that that the username and password you are using are for the same user with which the application is associated:

    OAuthException: invalid_grant error processing request

### Two-Factor Authentication

A 2FA token can be used by joining it to the password with a colon:

    reddit = praw.Reddit(client_id='SI8pN3DSbt0zor',
                         client_secret='xaxkj7HNh8kwg8e5t4m6KvSrbTI',
                         password='1guiwevlfo00esyy:955413',
                         user_agent='testscript by /u/fakebot3',
                         username='fakebot3')

However, for such an app there is little benefit to using 2FA. The token must be refreshed after one hour; therefore, the 2FA secret would have to be stored along with the rest of the credentials in order to generate the token, which defeats the point of having an extra credential beyond the password.

If you do choose to use 2FA, you must handle the `prawcore.OAuthException` that will be raised by API calls after one hour.

## Code Flow

A code flow application is useful for two primary purposes:

- You have an application and want to be able to access Reddit from your users’ accounts.
- You have a personal-use script application and you either want to * limit the access one of your PRAW-based programs has to Reddit * avoid the hassle of 2FA (described above) * not pass your username and password to PRAW (and thus not keep it in memory)

When registering your application you must provide a valid redirect uri. If you are running a website you will want to enter the appropriate callback URL and configure that endpoint to complete the code flow.

If you aren’t actually running a website, you can use the Obtaining a Refresh Token script to obtain `refresh_tokens`. Enter `http://localhost:8080` as the redirect uri when using this script.

Whether or not you use the script there are two processes involved in obtaining access or refresh tokens.

### Obtain the Authorization URL

The first step to completing the code flow is to obtain the authorization URL. You can do that as follows:

    reddit = praw.Reddit(client_id='SI8pN3DSbt0zor',
                         client_secret='xaxkj7HNh8kwg8e5t4m6KvSrbTI',
                         redirect_uri='http://localhost:8080',
                         user_agent='testscript by /u/fakebot3')
    print(reddit.auth.url(['identity'], '...', 'permanent'))

The above will output an authorization URL for a permanent token that has only the identity scope. See `url()` for more information on these parameters.

This URL should be accessed by the account that desires to authorize their Reddit access to your application. On completion of that flow, the user’s browser will be redirected to the specified `redirect_uri`. After extracting verifying the `state` and extracting the `code` you can obtain the refresh token via:

    print(reddit.auth.authorize(code))
    print(reddit.user.me())

The first line of output is the `refresh_token`. You can save this for later use (see Using a Saved Refresh Token).

The second line of output reveals the name of the Redditor that completed the code flow. It also indicates that the `reddit` instance is now associated with that account.

The code flow can be used with an installed application just as described above with one change: set the value of `client_secret` to `None` when initializing `Reddit`.

## Implicit Flow

The implicit flow requires a similar instantiation of the `Reddit` class as done in Code Flow, however, the token is returned directly as part of the redirect. For the implicit flow call `url()` like so:

    print(reddit.auth.url(['identity'], '...', implicit=True)

Then use `implicit()` to provide the authorization to the `Reddit` instance.

## Read Only Mode

All application types support a read only mode. Read only mode provides access to Reddit like a logged out user would see including the default Subreddits in the `reddit.front` listings.

In the absence of a `refresh_token` both Code Flow and Implicit Flow applications start in the read only mode. With such applications read only mode is disabled when `authorize()`, or `implicit()` are successfully called. Password Flow applications start up with read only mode disabled.

Read only mode can be toggled via:

    # Enable read only mode
    reddit.read_only = True

    # Disable read only mode (must have a valid authorization)
    reddit.read_only = False

### Aplication Only Flows

The following flows are the read only mode flows for Reddit applications

#### Application Only (Client Credentials)

This is the default flow for read only mode in script and web applications. The idea behind this is that Reddit can trust these applications as coming from a given developer, however the application requires no logged-in user context.

An installed application cannot use this flow, because it Reddit requires a `client_secret` to be given it this flow is being used. In other words, installed applications are not considered confidential clients.

#### Application Only (Installed Client)

This is the default flow for read only mode in installed applications. The idea behind this is that Reddit might not be able to trust these applications as coming from a given developer. This would be able to happen if someone other than the developer can potentially replicate the client information and then pretend to be the application, such as in installed applications where the end user could retrieve the `client_id`.

Note

No benefit is really gained from this in script or web apps. The one exception is for when a script or web app has multiple end users, this will allow you to give Reddit the information needed in order to distinguish different users of your app from each other (as the supplied device id should be a unique string per both device (in the case of a web app, server) and user (in the case of a web app, browser session).

## Using a Saved Refresh Token

A saved refresh token can be used to immediately obtain an authorized instance of `Reddit` like so:

    reddit = praw.Reddit(client_id='SI8pN3DSbt0zor',
                         client_secret='xaxkj7HNh8kwg8e5t4m6KvSrbTI',
                         refresh_token='WeheY7PwgeCZj4S3QgUcLhKE5S2s4eAYdxM',
                         user_agent='testscript by /u/fakebot3')
    print(reddit.auth.scopes())

The output from the above code displays which scopes are available on the `Reddit` instance.

Note

Observe that `redirect_uri` does not need to be provided in such cases. It is only needed when `url()` is used.