1 /*
2  * Copyright (c) 2017 Nathan Osman
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a copy
5  * of this software and associated documentation files (the "Software"), to
6  * deal in the Software without restriction, including without limitation the
7  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
8  * sell copies of the Software, and to permit persons to whom the Software is
9  * furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
20  * IN THE SOFTWARE.
21  */
22 
23 #ifndef QHTTPENGINE_HANDLER_H
24 #define QHTTPENGINE_HANDLER_H
25 
26 #include <QObject>
27 
28 #include "qhttpengine_export.h"
29 
30 class QRegExp;
31 
32 namespace QHttpEngine
33 {
34 
35 class Middleware;
36 class Socket;
37 
38 class QHTTPENGINE_EXPORT HandlerPrivate;
39 
40 /**
41  * @brief Base class for HTTP handlers
42  *
43  * When a request is received by a [Server](@ref QHttpEngine::Server), it
44  * invokes the route() method of the root handler which is used to determine
45  * what happens to the request. All HTTP handlers derive from this class and
46  * should override the protected process() method in order to process the
47  * request. Each handler also maintains a list of redirects and sub-handlers
48  * which are used in place of invoking process() when one of the patterns
49  * match.
50  *
51  * To add a redirect, use the addRedirect() method. The first parameter is a
52  * QRegExp pattern that the request path will be tested against. If it
53  * matches, an HTTP 302 redirect will be written to the socket and the request
54  * closed. For example, to have the root path "/" redirect to "/index.html":
55  *
56  * @code
57  * QHttpEngine::Handler handler;
58  * handler.addRedirect(QRegExp("^$"), "/index.html");
59  * @endcode
60  *
61  * To add a sub-handler, use the addSubHandler() method. Again, the first
62  * parameter is a QRegExp pattern. If the pattern matches, the portion of the
63  * path that matched the pattern is removed from the path and it is passed to
64  * the sub-handler's route() method. For example, to have a sub-handler
65  * invoked when the path begins with "/api/":
66  *
67  * @code
68  * QHttpEngine::Handler handler, subHandler;
69  * handler.addSubHandler(QRegExp("^api/"), &subHandler);
70  * @endcode
71  *
72  * If the request doesn't match any redirect or sub-handler patterns, it is
73  * passed along to the process() method, which is expected to either process
74  * the request or write an error to the socket. The default implementation of
75  * process() simply returns an HTTP 404 error.
76  */
77 class QHTTPENGINE_EXPORT Handler : public QObject
78 {
79     Q_OBJECT
80 
81 public:
82 
83     /**
84      * @brief Base constructor for a handler
85      */
86     explicit Handler(QObject *parent = 0);
87 
88     /**
89      * @brief Add middleware to the handler
90      */
91     void addMiddleware(Middleware *middleware);
92 
93     /**
94      * @brief Add a redirect for a specific pattern
95      *
96      * The pattern and path will be added to an internal list that will be
97      * used when the route() method is invoked to determine whether the
98      * request matches any patterns. The order of the list is preserved.
99      *
100      * The destination path may use "%1", "%2", etc. to refer to captured
101      * parts of the pattern. The client will receive an HTTP 302 redirect.
102      */
103     void addRedirect(const QRegExp &pattern, const QString &path);
104 
105     /**
106      * @brief Add a handler for a specific pattern
107      *
108      * The pattern and handler will be added to an internal list that will be
109      * used when the route() method is invoked to determine whether the
110      * request matches any patterns. The order of the list is preserved.
111      */
112     void addSubHandler(const QRegExp &pattern, Handler *handler);
113 
114     /**
115      * @brief Route an incoming request
116      */
117     void route(Socket *socket, const QString &path);
118 
119 protected:
120 
121     /**
122      * @brief Process a request
123      *
124      * This method should process the request either by fulfilling it, sending
125      * a redirect with
126      * [Socket::writeRedirect()](@ref QHttpEngine::Socket::writeRedirect), or
127      * writing an error to the socket using
128      * [Socket::writeError()](@ref QHttpEngine::Socket::writeError).
129      */
130     virtual void process(Socket *socket, const QString &path);
131 
132 private:
133 
134     HandlerPrivate *const d;
135     friend class HandlerPrivate;
136 };
137 
138 }
139 
140 #endif // QHTTPENGINE_HANDLER_H
141