| 1 | /* Copyright 2001,2006,2010,2012 Daniel F. Savarese |
| 2 | * |
| 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 |
| 6 | * |
| 7 | * https://www.savarese.org/software/ApacheLicense-2.0 |
| 8 | * |
| 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. |
| 14 | */ |
| 15 | |
| 16 | package org.savarese.barehttp; |
| 17 | |
| 18 | import java.io.*; |
| 19 | import java.net.*; |
| 20 | import java.text.*; |
| 21 | import java.util.*; |
| 22 | |
| 23 | import org.apache.oro.text.regex.*; |
| 24 | |
| 25 | /** |
| 26 | * An HTTPSession executes an HTTP conversation via an InputStream and |
| 27 | * OutputSream. It processes only one request and then terminates the |
| 28 | * session. Only HTTP/0.9, 1.0, and 1.1 GET requests and HTTP/1.0 and |
| 29 | * 1.1 HEAD requests are supported. The canonical pathname of served |
| 30 | * files is checked against the document root. If the file path does |
| 31 | * not fall under the document root, an HTTP "403 Forbidden Resource" |
| 32 | * error is returned. |
| 33 | * |
| 34 | * @author <a href="https://www.savarese.org/">Daniel F. Savarese</a> |
| 35 | */ |
| 36 | public class HTTPSession { |
| 37 | |
| 38 | final class Request { |
| 39 | static final int UNKNOWN_REQUEST = -1; |
| 40 | static final int SIMPLE_REQUEST = 0; |
| 41 | static final int GET_REQUEST = 1; |
| 42 | static final int HEAD_REQUEST = 2; |
| 43 | static final int HEADER = 3; |
| 44 | static final int HEADER_CONTINUATION = 4; |
| 45 | static final int END_OF_REQUEST = 5; |
| 46 | static final String DEFAULT_VERSION = "1.0"; |
| 47 | |
| 48 | int type; |
| 49 | HashMap<String,String> headers; |
| 50 | String version; |
| 51 | String uri; |
| 52 | |
| 53 | Request() { |
| 54 | headers = new HashMap<String,String>(); |
| 55 | reset(); |
| 56 | } |
| 57 | |
| 58 | void setVersion(String version) { |
| 59 | this.version = version; |
| 60 | } |
| 61 | |
| 62 | // unused |
| 63 | // String getVersion() { return version; } |
| 64 | |
| 65 | |
| 66 | void setType(int type) { |
| 67 | this.type = type; |
| 68 | } |
| 69 | |
| 70 | int getType() { return type; } |
| 71 | |
| 72 | void setHeaderValue(String field, String value) { |
| 73 | headers.put(field, value); |
| 74 | } |
| 75 | |
| 76 | String getHeaderValue(String field) { |
| 77 | return headers.get(field); |
| 78 | } |
| 79 | |
| 80 | void setURI(String uri) throws IOException { |
| 81 | this.uri = uri; |
| 82 | } |
| 83 | |
| 84 | String getURI() { return uri; } |
| 85 | |
| 86 | void reset() { |
| 87 | headers.clear(); |
| 88 | type = UNKNOWN_REQUEST; |
| 89 | version = DEFAULT_VERSION; |
| 90 | uri = null; |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | static final String URL_PATTERN_STRING = "([^ ?]*)(?:\\?[^ ]*)?"; |
| 95 | |
| 96 | static final String[] PATTERN_STRING = { |
| 97 | "^GET " + URL_PATTERN_STRING + "$", |
| 98 | "^GET " + URL_PATTERN_STRING + " HTTP/(\\d+\\.\\d+)$", |
| 99 | "^HEAD " + URL_PATTERN_STRING + " HTTP/(\\d+\\.\\d+)$", |
| 100 | "^(\\S+): (.*)$", |
| 101 | "^ (.*)$", |
| 102 | "^$" |
| 103 | }; |
| 104 | |
| 105 | static final String HTTP_VERSION = "HTTP/1.0"; |
| 106 | static final String DEFAULT_HEADERS = |
| 107 | "Server: BareHTTP @version@ (Java)\r\n" + |
| 108 | "Allow: GET, HEAD\r\n" + |
| 109 | "Connection: close\r\n"; |
| 110 | |
| 111 | static final String OK_STATUS = "200 OK"; |
| 112 | static final String FORBIDDEN_STATUS = "403 Forbidden Resource"; |
| 113 | static final String NOT_FOUND_STATUS = "404 Resource Not Found"; |
| 114 | static final String NOT_IMPLEMENTED_STATUS = "501 Not Implemented"; |
| 115 | |
| 116 | static final Pattern[] PATTERN; |
| 117 | static final String DATE_FORMAT = "EEE, d MMM yyyy hh:mm:ss z"; |
| 118 | static final Properties MimeTypes = new Properties(); |
| 119 | |
| 120 | BufferedReader input; |
| 121 | OutputStream output; |
| 122 | Perl5Matcher matcher; |
| 123 | Request request; |
| 124 | SimpleDateFormat dateFormat; |
| 125 | String documentRoot; |
| 126 | |
| 127 | static { |
| 128 | Perl5Compiler compiler = new Perl5Compiler(); |
| 129 | |
| 130 | PATTERN = new Perl5Pattern[PATTERN_STRING.length]; |
| 131 | |
| 132 | try { |
| 133 | for(int i = 0; i < PATTERN.length; ++i) { |
| 134 | PATTERN[i] = |
| 135 | compiler.compile(PATTERN_STRING[i], |
| 136 | Perl5Compiler.READ_ONLY_MASK); |
| 137 | } |
| 138 | } catch(MalformedPatternException e) { |
| 139 | // This should happen only during development. |
| 140 | throw new RuntimeException(e); |
| 141 | } |
| 142 | |
| 143 | try { |
| 144 | MimeTypes.load(HTTPSession.class.getResourceAsStream("mime.properties")); |
| 145 | } catch(IOException ioe) { |
| 146 | throw new RuntimeException(ioe); |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | boolean parseRequest() throws IOException { |
| 151 | String line; |
| 152 | int pattern; |
| 153 | MatchResult match; |
| 154 | String lastHeader = null; |
| 155 | |
| 156 | request.reset(); |
| 157 | |
| 158 | loop: |
| 159 | while(true) { |
| 160 | line = input.readLine(); |
| 161 | |
| 162 | if(line == null) { |
| 163 | break; |
| 164 | } |
| 165 | |
| 166 | |
| 167 | for(pattern = 0; pattern < PATTERN.length; ++pattern) { |
| 168 | if(matcher.matches(line, PATTERN[pattern])) { |
| 169 | break; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | match = matcher.getMatch(); |
| 174 | |
| 175 | switch(pattern) { |
| 176 | case Request.SIMPLE_REQUEST: |
| 177 | request.setType(pattern); |
| 178 | request.setURI(documentRoot + match.group(1)); |
| 179 | request.setVersion("0.9"); |
| 180 | break loop; |
| 181 | case Request.GET_REQUEST: |
| 182 | case Request.HEAD_REQUEST: |
| 183 | request.setType(pattern); |
| 184 | request.setURI(documentRoot + match.group(1)); |
| 185 | request.setVersion(match.group(2)); |
| 186 | break; |
| 187 | case Request.HEADER: |
| 188 | lastHeader = match.group(1); |
| 189 | request.setHeaderValue(lastHeader, match.group(2)); |
| 190 | break; |
| 191 | case Request.HEADER_CONTINUATION: |
| 192 | request.setHeaderValue(lastHeader, |
| 193 | request.getHeaderValue(lastHeader) + |
| 194 | match.group(1)); |
| 195 | break; |
| 196 | case Request.END_OF_REQUEST: |
| 197 | break loop; |
| 198 | default: |
| 199 | reportError(NOT_IMPLEMENTED_STATUS); |
| 200 | return false; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | return true; |
| 205 | } |
| 206 | |
| 207 | void processRequest() throws IOException { |
| 208 | int type = request.getType(); |
| 209 | |
| 210 | switch(type) { |
| 211 | case Request.SIMPLE_REQUEST: |
| 212 | case Request.GET_REQUEST: |
| 213 | case Request.HEAD_REQUEST: |
| 214 | File file = new File(request.getURI()); |
| 215 | |
| 216 | if(file.isDirectory()) { |
| 217 | file = new File(file, "index.html"); |
| 218 | } |
| 219 | |
| 220 | if(!file.exists()) { |
| 221 | reportError(NOT_FOUND_STATUS); |
| 222 | return; |
| 223 | } |
| 224 | |
| 225 | if(!validateFile(file)) { |
| 226 | reportError(FORBIDDEN_STATUS); |
| 227 | return; |
| 228 | } |
| 229 | |
| 230 | if(type != Request.SIMPLE_REQUEST) { |
| 231 | output.write((HTTP_VERSION + " " + OK_STATUS + "\r\nDate: " + |
| 232 | getDateHeader() + "\r\n" + |
| 233 | DEFAULT_HEADERS + "Last-Modified: " + |
| 234 | getDateHeader(file.lastModified()) + "\r\n" + |
| 235 | "Content-Length: " + file.length() + "\r\n" + |
| 236 | "Content-Type: " + getContentType(file) + |
| 237 | "\r\n\r\n").getBytes()); |
| 238 | } |
| 239 | |
| 240 | if(type == Request.HEAD_REQUEST) { |
| 241 | return; |
| 242 | } |
| 243 | |
| 244 | FileInputStream input = new FileInputStream(file); |
| 245 | byte[] buffer = new byte[1024]; |
| 246 | int bytes; |
| 247 | |
| 248 | while((bytes = input.read(buffer, 0, buffer.length)) != -1) { |
| 249 | output.write(buffer, 0, bytes); |
| 250 | } |
| 251 | input.close(); |
| 252 | break; |
| 253 | default: |
| 254 | reportError(NOT_IMPLEMENTED_STATUS); |
| 255 | return; |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | String getContentType(File file) throws IOException { |
| 260 | String path = file.getCanonicalPath(); |
| 261 | int index = path.lastIndexOf('.') + 1; |
| 262 | String type = MimeTypes.getProperty(path.substring(index)); |
| 263 | |
| 264 | if(type == null) { |
| 265 | type = "application/octet-stream"; |
| 266 | } |
| 267 | |
| 268 | return type; |
| 269 | } |
| 270 | |
| 271 | /** |
| 272 | * Makes a feeble attempt to confine the file to a tree |
| 273 | * rooted at the server's document directory. |
| 274 | */ |
| 275 | boolean validateFile(File file) throws IOException { |
| 276 | return (file.getCanonicalPath().startsWith(documentRoot)); |
| 277 | //return (file.getPath().startsWith(documentRoot)); |
| 278 | } |
| 279 | |
| 280 | void closeSession() throws IOException { |
| 281 | output.flush(); |
| 282 | output.close(); |
| 283 | input.close(); |
| 284 | } |
| 285 | |
| 286 | |
| 287 | String getDateHeader(long time) { |
| 288 | return dateFormat.format(new Date(time)); |
| 289 | } |
| 290 | |
| 291 | String getDateHeader() { |
| 292 | return getDateHeader(System.currentTimeMillis()); |
| 293 | } |
| 294 | |
| 295 | void reportError(String statusLine) throws IOException { |
| 296 | output.write((HTTP_VERSION + " " + statusLine + |
| 297 | "\r\nDate: " + getDateHeader() + "\r\n" + |
| 298 | DEFAULT_HEADERS + "\r\n" + |
| 299 | "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\r\n" + |
| 300 | "<HTML><HEAD>\r\n" + |
| 301 | "<TITLE>" + statusLine + "</TITLE>\r\n" + |
| 302 | "</HEAD><BODY>\r\n" + |
| 303 | "<H1>" + statusLine + "</H1>\r\n" + |
| 304 | "</BODY></HTML>\r\n").getBytes()); |
| 305 | } |
| 306 | |
| 307 | /** |
| 308 | * Creates an HTTPSession rooted at the specified document directory |
| 309 | * and communicating via the specified streams. |
| 310 | * |
| 311 | * @param documentRoot The fully qualified directory pathname to |
| 312 | * serve as the document root. |
| 313 | * @param in The InputStream via which the client submits its request. |
| 314 | * @param out The OutputStram via which the HTTPSession sends its reply. |
| 315 | */ |
| 316 | public HTTPSession(String documentRoot, InputStream in, OutputStream out) |
| 317 | throws IOException |
| 318 | { |
| 319 | input = new BufferedReader(new InputStreamReader(in, "ISO-8859-1")); |
| 320 | output = out; |
| 321 | matcher = new Perl5Matcher(); |
| 322 | request = new Request(); |
| 323 | dateFormat = new SimpleDateFormat(DATE_FORMAT); |
| 324 | dateFormat.setTimeZone(new SimpleTimeZone(0, "GMT")); |
| 325 | this.documentRoot = documentRoot; |
| 326 | } |
| 327 | |
| 328 | /** |
| 329 | * Executes the HTTP conversation and closes the session after |
| 330 | * satisfying the first request. |
| 331 | */ |
| 332 | public void execute() throws IOException { |
| 333 | if(parseRequest()) { |
| 334 | processRequest(); |
| 335 | } |
| 336 | closeSession(); |
| 337 | } |
| 338 | |
| 339 | } |
| 340 | |
