| 1 | dirplex(1) |
| 2 | ========== |
| 3 | |
| 4 | NAME |
| 5 | ---- |
| 6 | dirplex - Physical directory handler for ashd(7) |
| 7 | |
| 8 | SYNOPSIS |
| 9 | -------- |
| 10 | *dirplex* [*-hN*] [*-c* 'CONFIG'] 'DIR' |
| 11 | |
| 12 | DESCRIPTION |
| 13 | ----------- |
| 14 | |
| 15 | The *dirplex* handler maps URLs into physical files or directories, |
| 16 | and, having found a matching file or directory, it performs various |
| 17 | kinds of pattern-matching against its physical name to determine what |
| 18 | handler to call in order to serve the request. The mapping procedure |
| 19 | and pattern matching are described below. |
| 20 | |
| 21 | Having found a handler to serve a file or directory with, *dirplex* |
| 22 | adds the `X-Ash-File` header to the request with a path to the |
| 23 | physical file, before passing the request on to the handler. |
| 24 | |
| 25 | *dirplex* is a persistent handler, as defined in *ashd*(7). |
| 26 | |
| 27 | OPTIONS |
| 28 | ------- |
| 29 | |
| 30 | *-h*:: |
| 31 | |
| 32 | Print a brief help message to standard output and exit. |
| 33 | |
| 34 | *-N*:: |
| 35 | |
| 36 | Do not read the global configuration file `dirplex.rc`. |
| 37 | |
| 38 | *-c* 'CONFIG':: |
| 39 | |
| 40 | Read an extra configuration file. If 'CONFIG' contains any |
| 41 | slashes, it is opened by that exact name. Otherwise, it is |
| 42 | searched for in the same way as the global configuration file |
| 43 | (see CONFIGURATION below). |
| 44 | |
| 45 | URL-TO-FILE MAPPING |
| 46 | ------------------- |
| 47 | |
| 48 | Mapping URLs into physical files is an iterative procedure, each step |
| 49 | looking in one single physical directory, starting with 'DIR'. For |
| 50 | each step, a path element is stripped off the beginning of the rest |
| 51 | string and examined, the path element being either the leading part of |
| 52 | the rest string up until the first slash, or the entire rest string if |
| 53 | it contains no slashes. If the rest string is empty, the directory |
| 54 | being examined is considered the result of the mapping. Otherwise, any |
| 55 | escape sequences in the path element under consideration are unescaped |
| 56 | before examining it. |
| 57 | |
| 58 | If the path element names a directory in the current directory, the |
| 59 | procedure continues in that directory. If it names a file, that file |
| 60 | is considered the result of the mapping (even if the rest string has |
| 61 | not been exhausted yet). |
| 62 | |
| 63 | If the path element does not name anything in the directory under |
| 64 | consideration, but contains no dots, then the directory is searched |
| 65 | for a file whose name before the first dot matches the path |
| 66 | element. If there is such a file, it is considered the result of the |
| 67 | mapping. |
| 68 | |
| 69 | If the result of the mapping procedure is a directory, it is checked |
| 70 | for the presence of a filed named by the *index-file* configuration |
| 71 | directive (see CONFIGURATION below). If there is such a file, it is |
| 72 | considered the final result instead of the directory itself. If the |
| 73 | index file name contains no dots and there is no exact match, then, |
| 74 | again, the directory is searched for a file whose name before the |
| 75 | first dot matches the index file name. |
| 76 | |
| 77 | See also 404 RESPONSES below. |
| 78 | |
| 79 | CONFIGURATION |
| 80 | ------------- |
| 81 | |
| 82 | Configuration in *dirplex* comes from several sources. When *dirplex* |
| 83 | starts, unless the *-N* option is given, it tries to find a global |
| 84 | configuration file named `dirplex.rc`. It looks in all directories |
| 85 | named by the *PATH* environment variable, appended with `../etc`. For |
| 86 | example, then, if *PATH* is `/usr/local/bin:/bin:/usr/bin`, the |
| 87 | directories `/usr/local/etc`, `/etc` and `/usr/etc` are searched for |
| 88 | `dirplex.rc`, in that order. Only the first file found is used, should |
| 89 | there exist several. |
| 90 | |
| 91 | If the *-c* option is given to *dirplex*, it too specifies a |
| 92 | configuration file to load. If the name given contains any slashes, it |
| 93 | is opened by that exact name. Otherwise, it is searched for in the |
| 94 | same manner as the global configuration file. |
| 95 | |
| 96 | In addition, all directories traversed by *dirplex* when mapping a URL |
| 97 | into a physical file may contain a file called `.htrc`, which may |
| 98 | specify extra configuration options for all files in and beneath that |
| 99 | directory. |
| 100 | |
| 101 | `.htrc` files are checked periodically and reread if changed. The |
| 102 | global configuration file and any file named by the *-c* option, |
| 103 | however, are never reexamined. |
| 104 | |
| 105 | When using the configuration files for deciding what to do with a |
| 106 | found file, they are examined in order of their "distance" from that |
| 107 | file. `.htrc` files found in the directory or directories containing |
| 108 | the file are considered "closest" to the file under consideration, |
| 109 | followed by any configuration file named by the *-c* option, followed |
| 110 | by the global configuration file. |
| 111 | |
| 112 | Each configuration file is a sequence of configuration stanzas, each |
| 113 | stanza being an unindented starting line, followed by zero or more |
| 114 | indented follow-up lines adding options to the stanza. The starting |
| 115 | line of a stanza is referred to as a "configuration directive" |
| 116 | below. Each line is a sequence of whitespace-separated words. A word |
| 117 | may contain whitespace if such whitespace is escaped, either by |
| 118 | enclosing the word in double quotes, or by escaping individual |
| 119 | whitespace characters with a preceding backslash. Backslash quoting |
| 120 | may also be used to treat double quotes or another backslash literally |
| 121 | as part of the word. Empty lines are ignored, and lines whose first |
| 122 | character after leading whitespace is a hash character (`#`) are |
| 123 | treated as comments and ignored. |
| 124 | |
| 125 | The follow configuration directives are recognized: |
| 126 | |
| 127 | *index-file* ['FILENAME'...]:: |
| 128 | |
| 129 | The given 'FILENAMEs' are used for finding index files (see |
| 130 | URL-TO-FILE MAPPING above). Specifying *index-file* overrides |
| 131 | entirely any previous specification in a more distant |
| 132 | configuration file, rather than adding to it. Zero 'FILENAMEs' |
| 133 | may be given to turn off index file searching completely. The |
| 134 | *index-file* directive accepts no follow-up lines. |
| 135 | |
| 136 | *child* 'NAME':: |
| 137 | |
| 138 | Declares a named, persistent request handler (see *ashd*(7) |
| 139 | for a more detailed description of persistent handlers). It |
| 140 | must contain exactly one follow-up line, *exec* 'PROGRAM' |
| 141 | ['ARGS'...], specifying the program to execute and the |
| 142 | arguments to pass it. If given in a `.htrc` file, the program |
| 143 | will be started in the same directory as the `.htrc` file |
| 144 | itself. The *child* stanza itself serves as the identity of |
| 145 | the forked process -- only one child process will be forked |
| 146 | per stanza, and if that child process exits, it will be |
| 147 | restarted the next time the stanza would be used. If a `.htrc` |
| 148 | file containing *child* stanzas is reloaded, any currently |
| 149 | running children are reused for *child* stanzas in the new |
| 150 | file with matching names (even if the *exec* line has |
| 151 | changed). |
| 152 | |
| 153 | *fchild* 'NAME':: |
| 154 | |
| 155 | Declares a named, transient request handler (see *ashd*(7) for |
| 156 | a more detailed description of persistent handlers). It must |
| 157 | contain exactly one follow-up line, *exec* 'PROGRAM' |
| 158 | ['ARGS'...], specifying the program to execute and the |
| 159 | arguments to pass it. In addition to the specified arguments, |
| 160 | the HTTP method, raw URL and the rest string will be appended |
| 161 | added as described in *ashd*(7). If given in a `.htrc` file, |
| 162 | the program will be started in the same directory as the |
| 163 | `.htrc` file itself. |
| 164 | |
| 165 | *match* [*directory*]:: |
| 166 | |
| 167 | Specifies a filename pattern-matching rule. The |
| 168 | pattern-matching procedure and the follow-up lines accepted by |
| 169 | this stanza are described below, under MATCHING. |
| 170 | |
| 171 | *capture* 'HANDLER':: |
| 172 | |
| 173 | Only meaningful in `.htrc` files. If a *capture* directive is |
| 174 | specified, then the URL-to-file mapping procedure as described |
| 175 | above is aborted as soon as the directory containing the |
| 176 | `.htrc` file is encountered. The request is passed, with any |
| 177 | remaining rest string, to the specified 'HANDLER', which must |
| 178 | by a named request handler specified either in the same |
| 179 | `.htrc` file or elsewhere. The *capture* directive accepts no |
| 180 | follow-up lines. |
| 181 | |
| 182 | MATCHING |
| 183 | -------- |
| 184 | |
| 185 | When a file or directory has been found by the mapping procedure (see |
| 186 | URL-TO-FILE MAPPING above), the name of the physical file is examined |
| 187 | to determine a request handler to pass the request to. Note that only |
| 188 | the physical file name is ever considered; any logical request |
| 189 | parameters such as the request URL or the rest string are entirely |
| 190 | ignored. |
| 191 | |
| 192 | To match a file, any *match* stanzas specified by any `.htrc` file or |
| 193 | in the global configuration files are searched in order of their |
| 194 | "distance" (see CONFIGURATION above) from the actual file. If it is a |
| 195 | directory which is being considered, only *match* stanzas with the |
| 196 | *directory* parameter are considered; otherwise, if it is a file, only |
| 197 | *match* stanzas without the *directory* parameter are considered. |
| 198 | |
| 199 | A *match* stanza must contain at least one follow-up line specifying |
| 200 | match rules. All rules must match for the stanza as a whole to match. |
| 201 | The following rules are recognized: |
| 202 | |
| 203 | *filename* 'PATTERN'...:: |
| 204 | |
| 205 | Matches if the name of the file under consideration matches |
| 206 | any of the 'PATTERNs'. A 'PATTERN' is an ordinary glob |
| 207 | pattern, such as `*.php`. See *fnmatch*(3) for more |
| 208 | information. |
| 209 | |
| 210 | *pathname* 'PATTERN'...:: |
| 211 | |
| 212 | Matches if the entire path (relative as considered from the |
| 213 | root directory being served) of the file under consideration |
| 214 | matches any of the 'PATTERNs'. A 'PATTERN' is an ordinary glob |
| 215 | pattern, except that slashes are not matched by wildcards. See |
| 216 | *fnmatch*(3) for more information. |
| 217 | |
| 218 | *default*:: |
| 219 | |
| 220 | Matches if and only if no *match* stanza without a *default* |
| 221 | rule has matched. |
| 222 | |
| 223 | *local*:: |
| 224 | |
| 225 | Valid only in `.htrc` files, *local* matches if and only if |
| 226 | the file under consideration resides in the same directory as |
| 227 | the containing `.htrc` file. |
| 228 | |
| 229 | In addition to the rules, a *match* stanza must contain exactly one |
| 230 | follow-up line specifying the action to take if it matches. The |
| 231 | following actions are recognized: |
| 232 | |
| 233 | *handler* 'HANDLER':: |
| 234 | |
| 235 | 'HANDLER' must be a named handler (see CONFIGURATION |
| 236 | above). The named handler is searched for not only in the same |
| 237 | configuration file as the *match* stanza, but in all |
| 238 | configuration files that are valid for the file under |
| 239 | consideration, in order of distance. As such, a more deeply |
| 240 | nested `.htrc` file may override the specified handler without |
| 241 | having to specify any new *match* stanzas. |
| 242 | |
| 243 | *fork* 'PROGRAM' ['ARGS'...]:: |
| 244 | |
| 245 | Run a transient handler for this file, as if it were specified |
| 246 | by a *fchild* stanza. This action exists mostly for |
| 247 | convenience. |
| 248 | |
| 249 | 404 RESPONSES |
| 250 | ------------- |
| 251 | |
| 252 | Any of the following cases will result in a 404 response being sent to |
| 253 | the client. |
| 254 | |
| 255 | * Failure of the mapping procedure to find a matching physical file. |
| 256 | * Presence of a path element during mapping that begins with a dot. |
| 257 | * A path element which, after URL unescaping, contains slashes. |
| 258 | * The mapping procedure finding a file which is neither a directory |
| 259 | nor a regular file. |
| 260 | * Presence of a non-final but empty path element during mapping. |
| 261 | * A physical file having been found which is not being matched by any |
| 262 | *match* stanza. |
| 263 | |
| 264 | *dirplex* will send a built-in 404 response by default, but any |
| 265 | `.htrc` file or global configuration may define a request handler |
| 266 | named `.notfound` to customize the behavior. Note that, unlike |
| 267 | successful requests, such a handler will not be passed the |
| 268 | `X-Ash-File` header. |
| 269 | |
| 270 | The built-in `.notfound` handler can also be used in *match* or |
| 271 | *capture* stanzas. |
| 272 | |
| 273 | EXAMPLES |
| 274 | -------- |
| 275 | |
| 276 | The *sendfile*(1) program can be used to serve HTML files as follows. |
| 277 | |
| 278 | -------- |
| 279 | match |
| 280 | filename *.html |
| 281 | fork sendfile -c text/html |
| 282 | -------- |
| 283 | |
| 284 | Assuming the PHP CGI interpreter is installed on the system, PHP |
| 285 | scripts can be used with the following configuration, using the |
| 286 | *callcgi*(1) program. |
| 287 | |
| 288 | -------- |
| 289 | fchild php |
| 290 | exec callcgi -p php-cgi |
| 291 | match |
| 292 | filename *.php |
| 293 | handler php |
| 294 | -------- |
| 295 | |
| 296 | If there is a directory without an index file, a file listing can be |
| 297 | automatically generated by the *htls*(1) program as follows. |
| 298 | |
| 299 | -------- |
| 300 | match directory |
| 301 | default |
| 302 | fork htls |
| 303 | -------- |
| 304 | |
| 305 | If you want an entire directory to be dedicated to some external SCGI |
| 306 | script engine, you can use the *callscgi*(1) program to serve it as |
| 307 | follows. Note that *callscgi*, and therefore the script engine itself, |
| 308 | is started in the directory itself, so that arbitrary code modules or |
| 309 | data files can be put directly in that directory and easily found. |
| 310 | |
| 311 | -------- |
| 312 | child foo |
| 313 | exec callscgi scgi-wsgi -p . foo |
| 314 | |
| 315 | capture foo |
| 316 | -------- |
| 317 | |
| 318 | AUTHOR |
| 319 | ------ |
| 320 | Fredrik Tolf <fredrik@dolda2000.com> |
| 321 | |
| 322 | SEE ALSO |
| 323 | -------- |
| 324 | *ashd*(7) |