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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/gtest_prod_util.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "google_apis/gaia/oauth2_access_token_consumer.h"
     13 #include "google_apis/gaia/oauth2_access_token_fetcher.h"
     14 #include "net/url_request/url_fetcher_delegate.h"
     15 #include "url/gurl.h"
     16 
     17 class GoogleServiceAuthError;
     18 class OAuth2MintTokenFlowTest;
     19 
     20 namespace net {
     21 class URLFetcher;
     22 class URLRequestContextGetter;
     23 }
     24 
     25 // Base class for all classes that implement a flow to call OAuth2
     26 // enabled APIs.
     27 //
     28 // Given a refresh token, an access token, and a list of scopes an OAuth2
     29 // enabled API is called in the following way:
     30 // 1. Try the given access token to call the API.
     31 // 2. If that does not work, use the refresh token and scopes to generate
     32 //    a new access token.
     33 // 3. Try the new access token to call the API.
     34 //
     35 // This class abstracts the basic steps and exposes template methods
     36 // for sub-classes to implement for API specific details.
     37 class OAuth2ApiCallFlow
     38     : public net::URLFetcherDelegate,
     39       public OAuth2AccessTokenConsumer {
     40  public:
     41   // Creates an instance that works with the given data.
     42   // Note that |access_token| can be empty. In that case, the flow will skip
     43   // the first step (of trying an existing access token).
     44   OAuth2ApiCallFlow(
     45       net::URLRequestContextGetter* context,
     46       const std::string& refresh_token,
     47       const std::string& access_token,
     48       const std::vector<std::string>& scopes);
     49 
     50   virtual ~OAuth2ApiCallFlow();
     51 
     52   // Start the flow.
     53   virtual void Start();
     54 
     55   // OAuth2AccessTokenFetcher implementation.
     56   virtual void OnGetTokenSuccess(const std::string& access_token,
     57                                  const base::Time& expiration_time) OVERRIDE;
     58   virtual void OnGetTokenFailure(const GoogleServiceAuthError& error) OVERRIDE;
     59 
     60   // net::URLFetcherDelegate implementation.
     61   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
     62 
     63  protected:
     64   // Template methods for sub-classes.
     65 
     66   // Methods to help create HTTP request.
     67   virtual GURL CreateApiCallUrl() = 0;
     68   virtual std::string CreateApiCallBody() = 0;
     69   virtual std::string CreateApiCallBodyContentType();
     70 
     71   // Sub-classes can expose an appropriate observer interface by implementing
     72   // these template methods.
     73   // Called when the API call finished successfully.
     74   virtual void ProcessApiCallSuccess(const net::URLFetcher* source) = 0;
     75   // Called when the API call failed.
     76   virtual void ProcessApiCallFailure(const net::URLFetcher* source) = 0;
     77   // Called when a new access token is generated.
     78   virtual void ProcessNewAccessToken(const std::string& access_token) = 0;
     79   virtual void ProcessMintAccessTokenFailure(
     80       const GoogleServiceAuthError& error) = 0;
     81 
     82  private:
     83   enum State {
     84     INITIAL,
     85     API_CALL_STARTED,
     86     API_CALL_DONE,
     87     MINT_ACCESS_TOKEN_STARTED,
     88     MINT_ACCESS_TOKEN_DONE,
     89     ERROR_STATE
     90   };
     91 
     92   friend class OAuth2ApiCallFlowTest;
     93   FRIEND_TEST_ALL_PREFIXES(OAuth2ApiCallFlowTest, CreateURLFetcher);
     94 
     95   // Helper to create an instance of access token fetcher.
     96   // Caller owns the returned instance.
     97   // Note that this is virtual since it is mocked during unit testing.
     98   virtual OAuth2AccessTokenFetcher* CreateAccessTokenFetcher();
     99 
    100   // Creates an instance of URLFetcher that does not send or save cookies.
    101   // Template method CreateApiCallUrl is used to get the URL.
    102   // Template method CreateApiCallBody is used to get the body.
    103   // The URLFether's method will be GET if body is empty, POST otherwise.
    104   // Caller owns the returned instance.
    105   // Note that this is virtual since it is mocked during unit testing.
    106   virtual net::URLFetcher* CreateURLFetcher();
    107 
    108   // Helper methods to implement the state machine for the flow.
    109   void BeginApiCall();
    110   void EndApiCall(const net::URLFetcher* source);
    111   void BeginMintAccessToken();
    112   void EndMintAccessToken(const GoogleServiceAuthError* error);
    113 
    114   net::URLRequestContextGetter* context_;
    115   std::string refresh_token_;
    116   std::string access_token_;
    117   std::vector<std::string> scopes_;
    118 
    119   State state_;
    120   // Whether we have already tried minting an access token once.
    121   bool tried_mint_access_token_;
    122 
    123   scoped_ptr<net::URLFetcher> url_fetcher_;
    124   scoped_ptr<OAuth2AccessTokenFetcher> oauth2_access_token_fetcher_;
    125 
    126   DISALLOW_COPY_AND_ASSIGN(OAuth2ApiCallFlow);
    127 };
    128 
    129 #endif  // GOOGLE_APIS_GAIA_OAUTH2_API_CALL_FLOW_H_
    130