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1 | /* |
2 | * This file is open source software, licensed to you under the terms | |
3 | * of the Apache License, Version 2.0 (the "License"). See the NOTICE file | |
4 | * distributed with this work for additional information regarding copyright | |
5 | * ownership. You may not use this file except in compliance with the License. | |
6 | * | |
7 | * You may obtain a copy of the License at | |
8 | * | |
9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
10 | * | |
11 | * Unless required by applicable law or agreed to in writing, | |
12 | * software distributed under the License is distributed on an | |
13 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
14 | * KIND, either express or implied. See the License for the | |
15 | * specific language governing permissions and limitations | |
16 | * under the License. | |
17 | */ | |
18 | /* | |
19 | * Copyright 2015 Cloudius Systems | |
20 | */ | |
21 | ||
f67539c2 TL |
22 | #include <seastar/core/do_with.hh> |
23 | #include <seastar/core/loop.hh> | |
11fdf7f2 TL |
24 | #include <boost/algorithm/string/replace.hpp> |
25 | #include <seastar/http/transformers.hh> | |
26 | #include <list> | |
27 | ||
28 | namespace seastar { | |
29 | ||
30 | namespace httpd { | |
31 | ||
32 | using namespace std; | |
33 | ||
34 | struct potential_match_entry { | |
35 | const char* begin; | |
36 | const char* end; | |
37 | size_t pos; | |
38 | }; | |
39 | ||
40 | /*! | |
41 | * \brief holds the buffer replace object current state | |
42 | * The way the matching algorithm works, is that when there's a match | |
43 | * it will be the first entry | |
44 | */ | |
45 | class buffer_replace_state { | |
46 | std::list<potential_match_entry> _potential_match; | |
47 | ||
48 | public: | |
49 | using iterator = std::list<potential_match_entry>::iterator; | |
50 | ||
51 | void add_potential_match(const char* s, const char* e, size_t pos) { | |
52 | _potential_match.emplace_back(potential_match_entry{s, e, pos}); | |
53 | } | |
54 | ||
55 | iterator begin() { | |
56 | return _potential_match.begin(); | |
57 | } | |
58 | ||
59 | iterator end() { | |
60 | return _potential_match.end(); | |
61 | } | |
62 | ||
63 | bool empty() const { | |
64 | return _potential_match.empty(); | |
65 | } | |
66 | ||
67 | bool last() const { | |
68 | return _potential_match.size() == 1; | |
69 | } | |
70 | ||
71 | auto erase(const iterator& i) { | |
72 | return _potential_match.erase(i); | |
73 | } | |
74 | ||
75 | /*! | |
76 | * \brief gets the key/value position in the buffer_replace of the match | |
77 | */ | |
78 | size_t get_pos() const { | |
79 | return (*_potential_match.begin()).pos; | |
80 | } | |
81 | ||
82 | /*! | |
83 | * \brief gets the length of the remaining string | |
84 | */ | |
85 | size_t get_remaining_length() const { | |
86 | return _potential_match.begin()->end - _potential_match.begin()->begin; | |
87 | } | |
88 | ||
89 | void clear() { | |
90 | _potential_match.clear(); | |
91 | } | |
92 | }; | |
93 | ||
94 | /*! | |
95 | *\brief a helper class to replace strings in a buffer | |
96 | * The keys to replace are surrounded by braces | |
97 | */ | |
98 | class buffer_replace { | |
99 | std::vector<std::tuple<sstring, sstring>> _values; | |
100 | buffer_replace_state _current; | |
101 | const sstring& get_value(size_t pos) const; | |
102 | const sstring& get_key(size_t pos) const; | |
103 | public: | |
104 | /*! | |
105 | * \brief Add a key and value to be replaced | |
106 | */ | |
107 | buffer_replace& add(sstring key, sstring value) { | |
108 | _values.emplace_back(std::make_tuple("{{" + key + "}}", value)); | |
109 | return *this; | |
110 | } | |
111 | ||
112 | /*! | |
113 | * \brief if there are no more buffers to consume get | |
114 | * the remaining chars stored in the buffer_replace | |
115 | */ | |
116 | temporary_buffer<char> get_remaining(); | |
117 | ||
118 | /*! | |
119 | * \brief check if the given buffer still match any of the current potential matches | |
120 | * | |
121 | */ | |
122 | temporary_buffer<char> match(temporary_buffer<char>& buf); | |
123 | /*! | |
124 | * \brief replace the buffer content | |
125 | * | |
126 | * The returned result is after translation. The method consumes what it read | |
127 | * from the buf, so the caller should check that buf is not empty. | |
128 | * | |
129 | * For example: if buf is: "abcd{{key}}" | |
130 | * res = replace(buf); | |
131 | * | |
132 | * res will be "abcd" | |
133 | * and buf will be "{{key}}" | |
134 | */ | |
135 | temporary_buffer<char> replace(temporary_buffer<char>& buf); | |
136 | ||
137 | /*! | |
138 | * \brief check if we are currently in the middle of consuming | |
139 | */ | |
140 | bool is_consuming() const { | |
141 | return !_current.empty(); | |
142 | } | |
143 | }; | |
144 | ||
145 | ||
146 | class content_replace_data_sink_impl : public data_sink_impl { | |
147 | output_stream<char> _out; | |
148 | buffer_replace _br; | |
149 | public: | |
150 | content_replace_data_sink_impl(output_stream<char>&& out, std::vector<std::tuple<sstring,sstring>>&& key_value) : _out(std::move(out)) { | |
151 | for (auto& i : key_value) { | |
152 | _br.add(std::get<0>(i), std::get<1>(i)); | |
153 | } | |
154 | } | |
155 | ||
156 | virtual future<> put(net::packet data) override { | |
157 | return make_ready_future<>(); | |
158 | } | |
159 | ||
160 | using data_sink_impl::put; | |
161 | ||
162 | virtual future<> put(temporary_buffer<char> buf) override { | |
163 | if (buf.empty()) { | |
164 | return make_ready_future<>(); | |
165 | } | |
166 | return do_with(temporary_buffer<char>(std::move(buf)), [this] (temporary_buffer<char>& buf) { | |
167 | return repeat([&buf, this] { | |
168 | auto bf = _br.replace(buf); | |
169 | return _out.write(bf.get(), bf.size()).then([&buf] { | |
170 | return (buf.empty()) ? stop_iteration::yes : stop_iteration::no; | |
171 | }); | |
172 | }); | |
173 | }); | |
174 | } | |
175 | ||
176 | virtual future<> flush() override { | |
177 | return _out.flush(); | |
178 | } | |
179 | ||
180 | virtual future<> close() override { | |
181 | // if we are in the middle of a consuming a key | |
182 | // there will be no match, write the remaining. | |
183 | if (_br.is_consuming()) { | |
184 | return do_with(temporary_buffer<char>(_br.get_remaining()), [this](temporary_buffer<char>& buf) { | |
185 | return _out.write(buf.get(), buf.size()).then([this] { | |
186 | return _out.flush(); | |
187 | }); | |
188 | }); | |
189 | } | |
190 | return _out.flush(); | |
191 | } | |
192 | }; | |
193 | ||
194 | class content_replace_data_sink : public data_sink { | |
195 | public: | |
196 | content_replace_data_sink(output_stream<char>&& out, std::vector<std::tuple<sstring,sstring>> key_value) | |
197 | : data_sink(std::make_unique<content_replace_data_sink_impl>( | |
198 | std::move(out), std::move(key_value))) {} | |
199 | }; | |
200 | ||
1e59de90 | 201 | output_stream<char> content_replace::transform(std::unique_ptr<http::request> req, |
11fdf7f2 TL |
202 | const sstring& extension, output_stream<char>&& s) { |
203 | sstring host = req->get_header("Host"); | |
204 | if (host == "" || (this->extension != "" && extension != this->extension)) { | |
205 | return std::move(s); | |
206 | } | |
207 | sstring protocol = req->get_protocol_name(); | |
20effc67 TL |
208 | output_stream_options opts; |
209 | opts.trim_to_size = true; | |
210 | return output_stream<char>(content_replace_data_sink(std::move(s), {std::make_tuple("Protocol", protocol), std::make_tuple("Host", host)}), 32000, opts); | |
11fdf7f2 TL |
211 | |
212 | } | |
213 | ||
214 | /*! | |
215 | * \brief find the open brace that surround a parameter | |
216 | * it is either two consecutive braces or a single brace, if it's the last char in the buffer | |
217 | */ | |
218 | ssize_t find_braces(const char* s, const char* end) { | |
219 | for (size_t i = 0; s != end; s++, i++) { | |
220 | if (*s == '{' && ((s + 1) == end || *(s + 1) == '{')) { | |
221 | return i; | |
222 | } | |
223 | } | |
224 | return -1; | |
225 | } | |
226 | ||
227 | const sstring& buffer_replace::get_value(size_t pos) const { | |
228 | return std::get<1>(_values[pos]); | |
229 | } | |
230 | ||
231 | const sstring& buffer_replace::get_key(size_t pos) const { | |
232 | return std::get<0>(_values[pos]); | |
233 | } | |
234 | ||
235 | temporary_buffer<char> buffer_replace::match(temporary_buffer<char>& buf) { | |
236 | if (_current.empty()) { | |
237 | return temporary_buffer<char>(); | |
238 | } | |
239 | auto buf_len = buf.size(); | |
240 | auto first = _current.begin(); | |
241 | while (first != _current.end()) { | |
242 | auto& pos = first->begin; | |
243 | auto end = first->end; | |
244 | size_t len_compare = std::min(buf_len, static_cast<size_t>(end - pos)); | |
245 | if (strncmp(pos, buf.begin(), len_compare)) { | |
246 | // No match remove the entry unless it's the last one | |
247 | // In that case, there is no match | |
248 | // we should return what we consumed so far; | |
249 | if (_current.last()) { | |
250 | auto res = get_remaining(); | |
251 | _current.erase(first); | |
9f95a23c | 252 | return res; |
11fdf7f2 TL |
253 | } |
254 | first = _current.erase(first); | |
255 | } else { | |
256 | // we found a match | |
257 | if (pos + len_compare == end) { | |
258 | // this is a full match, there could be only one so this is the first | |
259 | // consume the buffer and return | |
260 | const sstring& value = get_value(_current.get_pos()); | |
261 | temporary_buffer<char> res(value.data(), value.size()); | |
262 | buf.trim_front(len_compare); | |
263 | _current.clear(); | |
9f95a23c | 264 | return res; |
11fdf7f2 TL |
265 | } |
266 | // only partial match | |
267 | pos += len_compare; | |
268 | ++first; | |
269 | } | |
270 | } | |
271 | // if we are here we run out of buffer | |
272 | buf.trim_front(buf_len); | |
273 | return temporary_buffer<char>(); | |
274 | } | |
275 | ||
276 | temporary_buffer<char> buffer_replace::get_remaining() { | |
277 | if (!is_consuming()) { | |
278 | return temporary_buffer<char>(); | |
279 | } | |
280 | size_t pos = _current.get_pos(); | |
281 | const sstring& key = get_key(pos); | |
282 | auto size = key.size() - _current.get_remaining_length(); | |
f67539c2 | 283 | return temporary_buffer<char>(key.data(), size); |
11fdf7f2 TL |
284 | } |
285 | ||
286 | temporary_buffer<char> buffer_replace::replace(temporary_buffer<char>& buf) { | |
287 | if (buf.empty()) { | |
288 | return std::move(buf); | |
289 | } | |
290 | if (is_consuming()) { | |
291 | return match(buf); | |
292 | } | |
293 | auto start = find_braces(buf.begin(), buf.end()); | |
294 | if (start >= 0) { | |
295 | // we found an opening brace that is followed by a second brace or buffer end. | |
296 | // 1. All values are a possible match | |
297 | // 2. We can output the beginning of the buffer | |
298 | // 3. Need to continue matching the remaining buffer | |
299 | size_t pos = 0; | |
300 | for (auto&& i : _values) { | |
301 | sstring& key = std::get<0>(i); | |
f67539c2 | 302 | _current.add_potential_match(key.data() + 1, key.data() + key.size(), pos++); |
11fdf7f2 TL |
303 | } |
304 | temporary_buffer<char> res = buf.share(0, start); | |
305 | buf.trim_front(start + 1); | |
306 | return res; | |
307 | } | |
308 | ||
309 | return std::move(buf); | |
310 | } | |
311 | ||
312 | } | |
313 | ||
314 | } |