Welcome to MSAL Python’s documentation!

You can find high level conceptual documentations in the project README and workable samples inside the project code base .

The documentation hosted here is for API Reference.

PublicClientApplication and ConfidentialClientApplication

MSAL proposes a clean separation between public client applications and confidential client applications.

They are implemented as two separated classes, with different methods for different authentication scenarios.

PublicClientApplication

class msal.PublicClientApplication(client_id, client_credential=None, **kwargs)
acquire_token_by_device_flow(flow, claims_challenge=None, **kwargs)

Obtain token by a device flow object, with customizable polling effect.

Parameters:
  • flow (dict) – A dict previously generated by initiate_device_flow(). By default, this method’s polling effect will block current thread. You can abort the polling loop at any time, by changing the value of the flow’s “expires_at” key to 0.
  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

A dict representing the json response from AAD:

  • A successful response would contain “access_token” key,
  • an error response would contain “error” and usually “error_description”.

acquire_token_by_username_password(username, password, scopes, claims_challenge=None, **kwargs)

Gets a token for a given resource via user credentials.

See this page for constraints of Username Password Flow. https://github.com/AzureAD/microsoft-authentication-library-for-python/wiki/Username-Password-Authentication

Parameters:
  • username (str) – Typically a UPN in the form of an email address.
  • password (str) – The password.
  • scopes (list[str]) – Scopes requested to access a protected API (a resource).
  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

A dict representing the json response from AAD:

  • A successful response would contain “access_token” key,
  • an error response would contain “error” and usually “error_description”.

initiate_device_flow(scopes=None, **kwargs)

Initiate a Device Flow instance, which will be used in acquire_token_by_device_flow().

Parameters:scopes (list[str]) – Scopes requested to access a protected API (a resource).
Returns:A dict representing a newly created Device Flow object.
  • A successful response would contain “user_code” key, among others
  • an error response would contain some other readable key/value pairs.

ConfidentialClientApplication

class msal.ConfidentialClientApplication(client_id, client_credential=None, authority=None, validate_authority=True, token_cache=None, http_client=None, verify=True, proxies=None, timeout=None, client_claims=None, app_name=None, app_version=None, client_capabilities=None)
acquire_token_for_client(scopes, claims_challenge=None, **kwargs)

Acquires token for the current confidential client, not for an end user.

Parameters:
  • scopes (list[str]) – (Required) Scopes requested to access a protected API (a resource).
  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

A dict representing the json response from AAD:

  • A successful response would contain “access_token” key,
  • an error response would contain “error” and usually “error_description”.

acquire_token_on_behalf_of(user_assertion, scopes, claims_challenge=None, **kwargs)

Acquires token using on-behalf-of (OBO) flow.

The current app is a middle-tier service which was called with a token representing an end user. The current app can use such token (a.k.a. a user assertion) to request another token to access downstream web API, on behalf of that user. See detail docs here .

The current middle-tier app has no user interaction to obtain consent. See how to gain consent upfront for your middle-tier app from this article. https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-on-behalf-of-flow#gaining-consent-for-the-middle-tier-application

Parameters:
  • user_assertion (str) – The incoming token already received by this app
  • scopes (list[str]) – Scopes required by downstream API (a resource).
  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

A dict representing the json response from AAD:

  • A successful response would contain “access_token” key,
  • an error response would contain “error” and usually “error_description”.

Shared Methods

Both PublicClientApplication and ConfidentialClientApplication have following methods inherited from their base class. You typically do not need to initiate this base class, though.

class msal.ClientApplication(client_id, client_credential=None, authority=None, validate_authority=True, token_cache=None, http_client=None, verify=True, proxies=None, timeout=None, client_claims=None, app_name=None, app_version=None, client_capabilities=None)
__init__(client_id, client_credential=None, authority=None, validate_authority=True, token_cache=None, http_client=None, verify=True, proxies=None, timeout=None, client_claims=None, app_name=None, app_version=None, client_capabilities=None)

Create an instance of application.

Parameters:
  • client_id (str) – Your app has a client_id after you register it on AAD.
  • client_credential (str) –

    For PublicClientApplication, you simply use None here. For ConfidentialClientApplication, it can be a string containing client secret, or an X509 certificate container in this form:

    {
        "private_key": "...-----BEGIN PRIVATE KEY-----...",
        "thumbprint": "A1B2C3D4E5F6...",
        "public_certificate": "...-----BEGIN CERTIFICATE-----..." (Optional. See below.)
    }
    

    Added in version 0.5.0: public_certificate (optional) is public key certificate which will be sent through ‘x5c’ JWT header only for subject name and issuer authentication to support cert auto rolls.

    Per specs, “the certificate containing the public key corresponding to the key used to digitally sign the JWS MUST be the first certificate. This MAY be followed by additional certificates, with each subsequent certificate being the one used to certify the previous one.” However, your certificate’s issuer may use a different order. So, if your attempt ends up with an error AADSTS700027 - “The provided signature value did not match the expected signature value”, you may try use only the leaf cert (in PEM/str format) instead.

  • client_claims (dict) –

    Added in version 0.5.0: It is a dictionary of extra claims that would be signed by by this ConfidentialClientApplication ‘s private key. For example, you can use {“client_ip”: “x.x.x.x”}. You may also override any of the following default claims:

    {
        "aud": the_token_endpoint,
        "iss": self.client_id,
        "sub": same_as_issuer,
        "exp": now + 10_min,
        "iat": now,
        "jti": a_random_uuid
    }
    
  • authority (str) – A URL that identifies a token authority. It should be of the format https://login.microsoftonline.com/your_tenant By default, we will use https://login.microsoftonline.com/common
  • validate_authority (bool) – (optional) Turns authority validation on or off. This parameter default to true.
  • cache (TokenCache) – Sets the token cache used by this ClientApplication instance. By default, an in-memory cache will be created and used.
  • http_client – (optional) Your implementation of abstract class HttpClient <msal.oauth2cli.http.http_client> Defaults to a requests session instance
  • verify – (optional) It will be passed to the verify parameter in the underlying requests library This does not apply if you have chosen to pass your own Http client
  • proxies – (optional) It will be passed to the proxies parameter in the underlying requests library This does not apply if you have chosen to pass your own Http client
  • timeout – (optional) It will be passed to the timeout parameter in the underlying requests library This does not apply if you have chosen to pass your own Http client
  • app_name – (optional) You can provide your application name for Microsoft telemetry purposes. Default value is None, means it will not be passed to Microsoft.
  • app_version – (optional) You can provide your application version for Microsoft telemetry purposes. Default value is None, means it will not be passed to Microsoft.
  • client_capabilities (list[str]) –

    (optional) Allows configuration of one or more client capabilities, e.g. [“CP1”].

    Client capability is meant to inform the Microsoft identity platform (STS) what this client is capable for, so STS can decide to turn on certain features. For example, if client is capable to handle claims challenge, STS can then issue CAE access tokens to resources knowing when the resource emits claims challenge the client will be capable to handle.

    Implementation details: Client capability is implemented using “claims” parameter on the wire, for now. MSAL will combine them into `claims parameter <https://openid.net/specs/openid-connect-core-1_0-final.html#ClaimsParameter`_ which you will later provide via one of the acquire-token request.

acquire_token_by_authorization_code(code, scopes, redirect_uri=None, nonce=None, claims_challenge=None, **kwargs)

The second half of the Authorization Code Grant.

Parameters:
  • code – The authorization code returned from Authorization Server.
  • scopes (list[str]) –

    (Required) Scopes requested to access a protected API (a resource).

    If you requested user consent for multiple resources, here you will typically want to provide a subset of what you required in AuthCode.

    OAuth2 was designed mostly for singleton services, where tokens are always meant for the same resource and the only changes are in the scopes. In AAD, tokens can be issued for multiple 3rd party resources. You can ask authorization code for multiple resources, but when you redeem it, the token is for only one intended recipient, called audience. So the developer need to specify a scope so that we can restrict the token to be issued for the corresponding audience.

  • nonce – If you provided a nonce when calling get_authorization_request_url(), same nonce should also be provided here, so that we’ll validate it. An exception will be raised if the nonce in id token mismatches.
  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

A dict representing the json response from AAD:

  • A successful response would contain “access_token” key,
  • an error response would contain “error” and usually “error_description”.

acquire_token_by_refresh_token(refresh_token, scopes)

Acquire token(s) based on a refresh token (RT) obtained from elsewhere.

You use this method only when you have old RTs from elsewhere, and now you want to migrate them into MSAL. Calling this method results in new tokens automatically storing into MSAL.

You do NOT need to use this method if you are already using MSAL. MSAL maintains RT automatically inside its token cache, and an access token can be retrieved when you call acquire_token_silent().

Parameters:
  • refresh_token (str) – The old refresh token, as a string.
  • scopes (list) – The scopes associate with this old RT. Each scope needs to be in the Microsoft identity platform (v2) format. See Scopes not resources.
Returns:

  • A dict contains “error” and some other keys, when error happened.
  • A dict contains no “error” key means migration was successful.

acquire_token_silent(scopes, account, authority=None, force_refresh=False, claims_challenge=None, **kwargs)

Acquire an access token for given account, without user interaction.

It is done either by finding a valid access token from cache, or by finding a valid refresh token from cache and then automatically use it to redeem a new access token.

This method will combine the cache empty and refresh error into one return value, None. If your app does not care about the exact token refresh error during token cache look-up, then this method is easier and recommended.

Internally, this method calls acquire_token_silent_with_error().

Parameters:claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:
  • A dict containing no “error” key, and typically contains an “access_token” key, if cache lookup succeeded.
  • None when cache lookup does not yield a token.
acquire_token_silent_with_error(scopes, account, authority=None, force_refresh=False, claims_challenge=None, **kwargs)

Acquire an access token for given account, without user interaction.

It is done either by finding a valid access token from cache, or by finding a valid refresh token from cache and then automatically use it to redeem a new access token.

This method will differentiate cache empty from token refresh error. If your app cares the exact token refresh error during token cache look-up, then this method is suitable. Otherwise, the other method acquire_token_silent() is recommended.

Parameters:
  • scopes (list[str]) – (Required) Scopes requested to access a protected API (a resource).
  • account – one of the account object returned by get_accounts(), or use None when you want to find an access token for this client.
  • force_refresh – If True, it will skip Access Token look-up, and try to find a Refresh Token to obtain a new Access Token.
  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

  • A dict containing no “error” key, and typically contains an “access_token” key, if cache lookup succeeded.
  • None when there is simply no token in the cache.
  • A dict containing an “error” key, when token refresh failed.

get_accounts(username=None)

Get a list of accounts which previously signed in, i.e. exists in cache.

An account can later be used in acquire_token_silent() to find its tokens.

Parameters:username – Filter accounts with this username only. Case insensitive.
Returns:A list of account objects. Each account is a dict. For now, we only document its “username” field. Your app can choose to display those information to end user, and allow user to choose one of his/her accounts to proceed.
get_authorization_request_url(scopes, login_hint=None, state=None, redirect_uri=None, response_type='code', prompt=None, nonce=None, domain_hint=None, claims_challenge=None, **kwargs)

Constructs a URL for you to start a Authorization Code Grant.

Parameters:
  • scopes (list[str]) – (Required) Scopes requested to access a protected API (a resource).
  • state (str) – Recommended by OAuth2 for CSRF protection.
  • login_hint (str) – Identifier of the user. Generally a User Principal Name (UPN).
  • redirect_uri (str) – Address to return to upon receiving a response from the authority.
  • response_type (str) –

    Default value is “code” for an OAuth2 Authorization Code grant.

    You could use other content such as “id_token” or “token”, which would trigger an Implicit Grant, but that is not recommended.

  • prompt (str) – By default, no prompt value will be sent, not even “none”. You will have to specify a value explicitly. Its valid values are defined in Open ID Connect specs https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest
  • nonce – A cryptographically random value used to mitigate replay attacks. See also OIDC specs.
  • domain_hint

    Can be one of “consumers” or “organizations” or your tenant domain “contoso.com”. If included, it will skip the email-based discovery process that user goes through on the sign-in page, leading to a slightly more streamlined user experience. More information on possible values here and here.

  • claims_challenge – The claims_challenge parameter requests specific claims requested by the resource provider in the form of a claims_challenge directive in the www-authenticate header to be returned from the UserInfo Endpoint and/or in the ID Token and/or Access Token. It is a string of a JSON object which contains lists of claims being requested from these locations.
Returns:

The authorization url as a string.

remove_account(account)

Sign me out and forget me from token cache

TokenCache

One of the parameter accepted by both PublicClientApplication and ConfidentialClientApplication is the TokenCache.

class msal.TokenCache

This is considered as a base class containing minimal cache behavior.

Although it maintains tokens using unified schema across all MSAL libraries, this class does not serialize/persist them. See subclass SerializableTokenCache for details on serialization.

add(event, now=None)

Handle a token obtaining event, and add tokens into cache.

Known side effects: This function modifies the input event in place.

You can subclass it to add new behavior, such as, token serialization. See SerializableTokenCache for example.

class msal.SerializableTokenCache

This serialization can be a starting point to implement your own persistence.

This class does NOT actually persist the cache on disk/db/etc.. Depending on your need, the following simple recipe for file-based persistence may be sufficient:

import os, atexit, msal
cache = msal.SerializableTokenCache()
if os.path.exists("my_cache.bin"):
    cache.deserialize(open("my_cache.bin", "r").read())
atexit.register(lambda:
    open("my_cache.bin", "w").write(cache.serialize())
    # Hint: The following optional line persists only when state changed
    if cache.has_state_changed else None
    )
app = msal.ClientApplication(..., token_cache=cache)
...
Variables:has_state_changed (bool) – Indicates whether the cache state in the memory has changed since last serialize() or deserialize() call.
add(event, **kwargs)

Handle a token obtaining event, and add tokens into cache.

Known side effects: This function modifies the input event in place.

deserialize(state)

Deserialize the cache from a state previously obtained by serialize()

serialize()

Serialize the current cache state into a string.

Indices and tables