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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef GOOGLE_APIS_GAIA_OAUTH2_API_CALL_FLOW_H_
      6 #define GOOGLE_APIS_GAIA_OAUTH2_API_CALL_FLOW_H_
      7 
      8 #include <string>
      9 
     10 #include "base/memory/scoped_ptr.h"
     11 #include "google_apis/gaia/oauth2_access_token_consumer.h"
     12 #include "google_apis/gaia/oauth2_access_token_fetcher.h"
     13 #include "net/url_request/url_fetcher_delegate.h"
     14 
     15 class GoogleServiceAuthError;
     16 class OAuth2MintTokenFlowTest;
     17 
     18 namespace net {
     19 class URLFetcher;
     20 class URLRequestContextGetter;
     21 }
     22 
     23 // Base class for all classes that implement a flow to call OAuth2
     24 // enabled APIs.
     25 //
     26 // Given a refresh token, an access token, and a list of scopes an OAuth2
     27 // enabled API is called in the following way:
     28 // 1. Try the given access token to call the API.
     29 // 2. If that does not work, use the refresh token and scopes to generate
     30 //    a new access token.
     31 // 3. Try the new access token to call the API.
     32 //
     33 // This class abstracts the basic steps and exposes template methods
     34 // for sub-classes to implement for API specific details.
     35 class OAuth2ApiCallFlow
     36     : public net::URLFetcherDelegate,
     37       public OAuth2AccessTokenConsumer {
     38  public:
     39   // Creates an instance that works with the given data.
     40   // Note that |access_token| can be empty. In that case, the flow will skip
     41   // the first step (of trying an existing access token).
     42   OAuth2ApiCallFlow(
     43       net::URLRequestContextGetter* context,
     44       const std::string& refresh_token,
     45       const std::string& access_token,
     46       const std::vector<std::string>& scopes);
     47 
     48   virtual ~OAuth2ApiCallFlow();
     49 
     50   // Start the flow.
     51   virtual void Start();
     52 
     53   // OAuth2AccessTokenFetcher implementation.
     54   virtual void OnGetTokenSuccess(const std::string& access_token,
     55                                  const base::Time& expiration_time) OVERRIDE;
     56   virtual void OnGetTokenFailure(const GoogleServiceAuthError& error) OVERRIDE;
     57 
     58   // net::URLFetcherDelegate implementation.
     59   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
     60 
     61  protected:
     62   // Template methods for sub-classes.
     63 
     64   // Methods to help create HTTP request.
     65   virtual GURL CreateApiCallUrl() = 0;
     66   virtual std::string CreateApiCallBody() = 0;
     67 
     68   // Sub-classes can expose an appropriate observer interface by implementing
     69   // these template methods.
     70   // Called when the API call finished successfully.
     71   virtual void ProcessApiCallSuccess(const net::URLFetcher* source) = 0;
     72   // Called when the API call failed.
     73   virtual void ProcessApiCallFailure(const net::URLFetcher* source) = 0;
     74   // Called when a new access token is generated.
     75   virtual void ProcessNewAccessToken(const std::string& access_token) = 0;
     76   virtual void ProcessMintAccessTokenFailure(
     77       const GoogleServiceAuthError& error) = 0;
     78 
     79  private:
     80   enum State {
     81     INITIAL,
     82     API_CALL_STARTED,
     83     API_CALL_DONE,
     84     MINT_ACCESS_TOKEN_STARTED,
     85     MINT_ACCESS_TOKEN_DONE,
     86     ERROR_STATE
     87   };
     88 
     89   friend class OAuth2ApiCallFlowTest;
     90   FRIEND_TEST_ALL_PREFIXES(OAuth2ApiCallFlowTest, CreateURLFetcher);
     91 
     92   // Helper to create an instance of access token fetcher.
     93   // Caller owns the returned instance.
     94   // Note that this is virtual since it is mocked during unit testing.
     95   virtual OAuth2AccessTokenFetcher* CreateAccessTokenFetcher();
     96 
     97   // Creates an instance of URLFetcher that does not send or save cookies.
     98   // Template method CreateApiCallUrl is used to get the URL.
     99   // Template method CreateApiCallBody is used to get the body.
    100   // The URLFether's method will be GET if body is empty, POST otherwise.
    101   // Caller owns the returned instance.
    102   // Note that this is virtual since it is mocked during unit testing.
    103   virtual net::URLFetcher* CreateURLFetcher();
    104 
    105   // Helper methods to implement the state machine for the flow.
    106   void BeginApiCall();
    107   void EndApiCall(const net::URLFetcher* source);
    108   void BeginMintAccessToken();
    109   void EndMintAccessToken(const GoogleServiceAuthError* error);
    110 
    111   net::URLRequestContextGetter* context_;
    112   std::string refresh_token_;
    113   std::string access_token_;
    114   std::vector<std::string> scopes_;
    115 
    116   State state_;
    117   // Whether we have already tried minting an access token once.
    118   bool tried_mint_access_token_;
    119 
    120   scoped_ptr<net::URLFetcher> url_fetcher_;
    121   scoped_ptr<OAuth2AccessTokenFetcher> oauth2_access_token_fetcher_;
    122 
    123   DISALLOW_COPY_AND_ASSIGN(OAuth2ApiCallFlow);
    124 };
    125 
    126 #endif  // GOOGLE_APIS_GAIA_OAUTH2_API_CALL_FLOW_H_
    127