## org.apache.http.auth
Interface AuthScheme

All Known Subinterfaces:
  ContextAwareAuthScheme

All Known Implementing Classes:
  AuthSchemeBase, BasicScheme, DigestScheme, NegotiateScheme, NTLMScheme, RFC2617Scheme

    public interface AuthScheme

This interface represents an abstract challenge-response oriented authentication scheme.

An authentication scheme should be able to support the following functions:

- Parse and process the challenge sent by the target server in response to request for a protected resource
- Provide its textual designation
- Provide its parameters, if available
- Provide the realm this authentication scheme is applicable to, if available
- Generate authorization string for the given set of credentials and the HTTP request in response to the authorization challenge.

Authentication schemes may be stateful involving a series of challenge-response exchanges.

IMPORTANT: implementations of this interface MUST also implement `ContextAwareAuthScheme` interface in order to remain API compatible with newer versions of HttpClient.

Since:
  4.0

Method Summary
`Header` `authenticate(Credentials credentials, HttpRequest request)` Deprecated. Use `ContextAwareAuthScheme.authenticate(Credentials, HttpRequest, org.apache.http.protocol.HttpContext)`
`String` `getParameter(String name)` Returns authentication parameter with the given name, if available.
`String` `getRealm()` Returns authentication realm.
`String` `getSchemeName()` Returns textual designation of the given authentication scheme.
`boolean` `isComplete()` Authentication process may involve a series of challenge-response exchanges.
`boolean` `isConnectionBased()` Tests if the authentication scheme is provides authorization on a per connection basis instead of usual per request basis
`void` `processChallenge(Header header)` Processes the given challenge token.

Method Detail

### processChallenge

    void processChallenge(Header header)
                          throws MalformedChallengeException

  Processes the given challenge token. Some authentication schemes may involve multiple challenge-response exchanges. Such schemes must be able to maintain the state information when dealing with sequential challenges

  Parameters:
    `header` - the challenge header
  Throws:
    `MalformedChallengeException`

### getSchemeName

    String getSchemeName()

  Returns textual designation of the given authentication scheme.

  Returns:
    the name of the given authentication scheme

### getParameter

    String getParameter(String name)

  Returns authentication parameter with the given name, if available.

  Parameters:
    `name` - The name of the parameter to be returned
  Returns:
    the parameter with the given name

### getRealm

    String getRealm()

  Returns authentication realm. If the concept of an authentication realm is not applicable to the given authentication scheme, returns `null`.

  Returns:
    the authentication realm

### isConnectionBased

    boolean isConnectionBased()

  Tests if the authentication scheme is provides authorization on a per connection basis instead of usual per request basis

  Returns:
    `true` if the scheme is connection based, `false` if the scheme is request based.

### isComplete

    boolean isComplete()

  Authentication process may involve a series of challenge-response exchanges. This method tests if the authorization process has been completed, either successfully or unsuccessfully, that is, all the required authorization challenges have been processed in their entirety.

  Returns:
    `true` if the authentication process has been completed, `false` otherwise.

### authenticate

    @Deprecated
    Header authenticate(Credentials credentials,
                                   HttpRequest request)
                        throws AuthenticationException

  Deprecated. Use `ContextAwareAuthScheme.authenticate(Credentials, HttpRequest, org.apache.http.protocol.HttpContext)`

  Produces an authorization string for the given set of `Credentials`.

  Parameters:
    `credentials` - The set of credentials to be used for athentication
    `request` - The request being authenticated
  Returns:
    the authorization string
  Throws:
    `AuthenticationException` - if authorization string cannot be generated due to an authentication failure

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