1 //===-- llvm/Support/HTTPClient.h - HTTP client library ---------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file contains the declarations of the HTTPClient library for issuing
11 /// HTTP requests and handling the responses.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_DEBUGINFOD_HTTPCLIENT_H
16 #define LLVM_DEBUGINFOD_HTTPCLIENT_H
17 
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/Support/Error.h"
21 #include "llvm/Support/MemoryBuffer.h"
22 
23 #include <chrono>
24 
25 namespace llvm {
26 
27 enum class HTTPMethod { GET };
28 
29 /// A stateless description of an outbound HTTP request.
30 struct HTTPRequest {
31   SmallString<128> Url;
32   SmallVector<std::string, 0> Headers;
33   HTTPMethod Method = HTTPMethod::GET;
34   bool FollowRedirects = true;
35   HTTPRequest(StringRef Url);
36 };
37 
38 bool operator==(const HTTPRequest &A, const HTTPRequest &B);
39 
40 /// A handler for state updates occurring while an HTTPRequest is performed.
41 /// Can trigger the client to abort the request by returning an Error from any
42 /// of its methods.
43 class HTTPResponseHandler {
44 public:
45   /// Processes an additional chunk of bytes of the HTTP response body.
46   virtual Error handleBodyChunk(StringRef BodyChunk) = 0;
47 
48 protected:
49   ~HTTPResponseHandler();
50 };
51 
52 /// A reusable client that can perform HTTPRequests through a network socket.
53 class HTTPClient {
54 #ifdef LLVM_ENABLE_CURL
55   void *Curl = nullptr;
56 #endif
57 
58 public:
59   HTTPClient();
60   ~HTTPClient();
61 
62   static bool IsInitialized;
63 
64   /// Returns true only if LLVM has been compiled with a working HTTPClient.
65   static bool isAvailable();
66 
67   /// Must be called at the beginning of a program, while it is a single thread.
68   static void initialize();
69 
70   /// Must be called at the end of a program, while it is a single thread.
71   static void cleanup();
72 
73   /// Sets the timeout for the entire request, in milliseconds. A zero or
74   /// negative value means the request never times out.
75   void setTimeout(std::chrono::milliseconds Timeout);
76 
77   /// Performs the Request, passing response data to the Handler. Returns all
78   /// errors which occur during the request. Aborts if an error is returned by a
79   /// Handler method.
80   Error perform(const HTTPRequest &Request, HTTPResponseHandler &Handler);
81 
82   /// Returns the last received response code or zero if none.
83   unsigned responseCode();
84 };
85 
86 } // end namespace llvm
87 
88 #endif // LLVM_DEBUGINFOD_HTTPCLIENT_H
89