1// Copyright 2014 The Chromium OS 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 LIBBRILLO_BRILLO_HTTP_HTTP_CONNECTION_H_
6#define LIBBRILLO_BRILLO_HTTP_HTTP_CONNECTION_H_
7
8#include <memory>
9#include <string>
10#include <vector>
11
12#include <base/callback_forward.h>
13#include <base/macros.h>
14#include <brillo/brillo_export.h>
15#include <brillo/errors/error.h>
16#include <brillo/http/http_transport.h>
17#include <brillo/streams/stream.h>
18
19namespace brillo {
20namespace http {
21
22class Response;
23
24///////////////////////////////////////////////////////////////////////////////
25// Connection class is the base class for HTTP communication session.
26// It abstracts the implementation of underlying transport library (ex libcurl).
27// When the Connection-derived class is constructed, it is pre-set up with
28// basic initialization information necessary to initiate the server request
29// connection (such as the URL, request method, etc - see
30// Transport::CreateConnection() for more details). But most implementations
31// would not probably initiate the physical connection until SendHeaders
32// is called.
33// You normally shouldn't worry about using this class directly.
34// http::Request and http::Response classes use it for communication.
35// Effectively this class is the interface for the request/response objects to
36// the transport-specific instance of the communication channel with the
37// destination server. It is created by Transport as part of initiating
38// the connection to the destination URI and is shared between the request and
39// response object until all the data is sent to the server and the response
40// is received. The class does NOT represent a persistent TCP connection though
41// (e.g. in keep-alive scenarios).
42///////////////////////////////////////////////////////////////////////////////
43class BRILLO_EXPORT Connection
44    : public std::enable_shared_from_this<Connection> {
45 public:
46  explicit Connection(const std::shared_ptr<Transport>& transport)
47      : transport_(transport) {}
48  virtual ~Connection() = default;
49
50  // The following methods are used by http::Request object to initiate the
51  // communication with the server, send the request data and receive the
52  // response.
53
54  // Called by http::Request to initiate the connection with the server.
55  // This normally opens the socket and sends the request headers.
56  virtual bool SendHeaders(const HeaderList& headers,
57                           brillo::ErrorPtr* error) = 0;
58  // If needed, this function can be called to send the request body data.
59  virtual bool SetRequestData(StreamPtr stream, brillo::ErrorPtr* error) = 0;
60  // If needed, this function can be called to customize where the response
61  // data is streamed to.
62  virtual void SetResponseData(StreamPtr stream) = 0;
63  // This function is called when all the data is sent off and it's time
64  // to receive the response data. The method will block until the whole
65  // response message is received, or if an error occur in which case the
66  // function will return false and fill the error details in |error| object.
67  virtual bool FinishRequest(brillo::ErrorPtr* error) = 0;
68  // Send the request asynchronously and invoke the callback with the response
69  // received. Returns the ID of the pending async request.
70  virtual RequestID FinishRequestAsync(const SuccessCallback& success_callback,
71                                       const ErrorCallback& error_callback) = 0;
72
73  // The following methods are used by http::Response object to obtain the
74  // response data. They are used only after the response data has been received
75  // since the http::Response object is not constructed until
76  // Request::GetResponse()/Request::GetResponseAndBlock() methods are called.
77
78  // Returns the HTTP status code (e.g. 200 for success).
79  virtual int GetResponseStatusCode() const = 0;
80  // Returns the status text (e.g. for error 403 it could be "NOT AUTHORIZED").
81  virtual std::string GetResponseStatusText() const = 0;
82  // Returns the HTTP protocol version (e.g. "HTTP/1.1").
83  virtual std::string GetProtocolVersion() const = 0;
84  // Returns the value of particular response header, or empty string if the
85  // headers wasn't received.
86  virtual std::string GetResponseHeader(
87      const std::string& header_name) const = 0;
88  // Returns the response data stream. This function can be called only once
89  // as it transfers ownership of the data stream to the caller. Subsequent
90  // calls will fail with "Stream closed" error.
91  // Returns empty stream on failure and fills in the error information in
92  // |error| object.
93  virtual StreamPtr ExtractDataStream(brillo::ErrorPtr* error) = 0;
94
95 protected:
96  // |transport_| is mainly used to keep the object alive as long as the
97  // connection exists. But some implementations of Connection could use
98  // the Transport-derived class for their own needs as well.
99  std::shared_ptr<Transport> transport_;
100
101 private:
102  DISALLOW_COPY_AND_ASSIGN(Connection);
103};
104
105}  // namespace http
106}  // namespace brillo
107
108#endif  // LIBBRILLO_BRILLO_HTTP_HTTP_CONNECTION_H_
109