1 // Copyright (C) 2013 Google Inc.
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
7 // http://www.apache.org/licenses/LICENSE-2.0
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
15 // An object to retrieve data.
17 #ifndef I18N_ADDRESSINPUT_RETRIEVER_H_
18 #define I18N_ADDRESSINPUT_RETRIEVER_H_
20 #include <libaddressinput/callback.h>
21 #include <libaddressinput/util/basictypes.h>
22 #include <libaddressinput/util/scoped_ptr.h>
28 namespace addressinput {
33 // Manages downloading data and caching it locally. Sample usage:
34 // scoped_ptr<Downloader> downloader(new Downloader);
35 // scoped_ptr<Storage> storage(new Storage);
36 // Retriever retriever("https://i18napis.appspot.com/ssl-aggregate-address/",
37 // downloader.Pass(), storage.Pass());
38 // retriever.Retrieve("data/CA/AB--fr",
39 // BuildCallback(this, &MyClass::OnDataRetrieved));
42 typedef i18n::addressinput::Callback<std::string, std::string> Callback;
44 Retriever(const std::string& validation_data_url,
45 scoped_ptr<Downloader> downloader,
46 scoped_ptr<Storage> storage);
49 // Retrieves the data for |key| and invokes the |retrieved| callback. Checks
50 // for the data in storage first. If storage does not have the data for |key|,
51 // then downloads the data and places it in storage.
52 void Retrieve(const std::string& key, scoped_ptr<Callback> retrieved);
55 friend class RetrieverTest;
57 // Callback for when a rule is retrieved from |storage_|.
58 void OnDataRetrievedFromStorage(bool success,
59 const std::string& key,
60 const std::string& stored_data);
62 // Callback for when a rule is retrieved by |downloader_|.
63 void OnDownloaded(bool success,
64 const std::string& url,
65 scoped_ptr<std::string> downloaded_data);
67 // Returns the URL where the |key| can be retrieved. For example, returns
68 // "https://i18napis.appspot.com/ssl-aggregate-address/data/US" for input
69 // "data/US". Assumes that the input string is a valid URL segment.
70 std::string GetUrlForKey(const std::string& key) const;
72 // Returns the key for the |url|. For example, returns "data/US" for
73 // "https://i18napis.appspot.com/ssl-aggregate-address/data/US". If the |url|
74 // does not start with |validation_data_url| that was passed to the
75 // constructor, then returns an empty string. (This can happen if the user of
76 // the library returns a bad URL in their Downloader implementation.)
77 std::string GetKeyForUrl(const std::string& url) const;
79 // Returns true if the |url| starts with |validation_data_url| that was passed
80 // to the constructor.
81 bool IsValidationDataUrl(const std::string& url) const;
83 // Looks up the callback for |key| in |requests_|, removes it from the map and
84 // invokes it with |key|, |success|, and |data| parameters.
85 void InvokeCallbackForKey(const std::string& key,
87 const std::string& data);
89 const std::string validation_data_url_;
90 scoped_ptr<Downloader> downloader_;
91 scoped_ptr<Storage> storage_;
93 // Holds pending requests. The callback pointers are owned.
94 std::map<std::string, Callback*> requests_;
96 // Holds data from storage that has expired timestamps. If a download fails,
97 // then this data is used as fallback.
98 std::map<std::string, std::string> stale_data_;
100 DISALLOW_COPY_AND_ASSIGN(Retriever);
103 } // namespace addressinput
106 #endif // I18N_ADDRESSINPUT_RETRIEVER_H_