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[paraslash.git] / README.mysql
1 README.mysql
2 ============
3
4 This file describes how to use the mysql audio file selector which
5 comes with the paraslash package.
6
7 It assumes you have already installed mysql and paraslash as described
8 in INSTALL, so read README and INSTALL before proceeding.
9
10 First of all, make sure that
11
12 - mysqld is running
13
14 - para_server is running and compiled with mysql support
15 (type "para_client si" to find out)
16
17 - the user who runs para_client has the paraslash DB_WRITE
18 and DB_READ permissions set in server.users
19
20 - the user who runs para_server has create privileges on the
21 mysql server.
22
23 Remember: If something doesn't work as expected, look at the server
24 log file and/or increase output verbosity by using the -l switch for
25 server and client.
26
27
28 Specify mysql data (port, passwd,...)
29 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
30
31 Type
32
33 para_server -h
34
35 and look at the mysql options. You may either specify these options
36 in ~/.paraslash/server.conf or directly at the command line (not
37 recommended for passwd option). Don't forget to do
38
39 chmod 600 ~/.paraslash/server.conf
40
41 as this file contains the mysql passwd. To make these changes take
42 effect you'll need to do
43
44 para_client hup
45
46 Or, restart the server.
47
48 Switch to the mysql audio file selector
49 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
50
51 The command
52
53 para_client chs
54
55 prints the name of the current selector. Try
56
57 para_client chs mysql
58
59 to switch to the mysql selector. If this doesn't work, it means that
60 some required config options were not specified (check the log for
61 more info) or that para_server was built without mysql support. Type
62
63 para_client si
64
65 to find out. If mysql is not mentioned as a supported selector,
66 you'll have to recompile.
67
68
69 Create a new database
70 ~~~~~~~~~~~~~~~~~~~~~
71
72 Once the mysql selector is activated, create the database:
73
74 para_client cdb
75 para_client chs mysql
76
77 The second command forces para_server to re-init the mysql selector.
78 Check the log. There should not be any warnings or errors.
79
80
81 Fill your database with content
82 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
83
84 para_client upd
85
86 If this command fails, it most likely means the audio file directory
87 (given in the server configuration file) does not exist, is empty,
88 not readable, or contains different files with identical basenames. Fix
89 this problem before proceeding.
90
91 The command
92
93 para_client ls
94
95 prints the list of all files known by the mysql selector. If the list
96 is empty, double check the mysql_audio_file_dir option.
97
98
99 Create a stream which selects all songs
100 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
101
102 To keep it simple, let's only define the stream "all_songs". See below for
103 advanced stream usage.
104
105 para_client stradd all_songs < /dev/null
106 para_client sl 10 all_songs
107
108 The latter command should show you ten filenames.
109
110
111 Change to the all_songs stream
112 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
113
114 para_client cs all_songs
115
116 You should now be able to start streaming with
117
118 para_client play
119
120
121 Attribute usage
122 ~~~~~~~~~~~~~~~
123
124 An attribute is simply a bit which can be set for each audio file
125 individually. You may have as many attributes as you like. A new
126 attribute "test" is created by
127
128 para_client na test
129
130 and
131 para_client laa
132
133 lists all available attributes. You can set the "test" attribute for
134 the current audio file by executing
135
136 para_client sa test+
137
138 or for any particular audio file by
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140 para_client sa test+ filename
141
142 Unset the attribute "test" for the current audio file with
143
144 para_client sa test-
145
146 and drop the test attribute entirely from the database with
147
148 para_client da test
149
150 Stream usage
151 ~~~~~~~~~~~~
152
153 A stream is a pair of expressions in terms of attributes and other data
154 contained in the database. The first, boolian, expression determines
155 the set of audio files which are admissible in this stream. The second,
156 integer, expression determines the order in which admissible files
157 are going to be fed to the audio file sender(s).
158
159 To create a new stream called "my_stream", put arbitrary many (including
160 none) accept or deny lines and one or zero score lines into some
161 temporary file, say tmpfile. An accept/deny/score line consists of
162 an identifier ("accept:", "deny:", or "score:"), followed by an
163 expression. The command
164
165 para_client stradd my_stream < tmpfile
166
167 adds the stream "my_stream" to the table of streams.
168
169 If the stream definition is really short, you may also just pipe it to
170 the client rather than using temporary files. Like this:
171
172 echo "$MYSTREAMDEF" | para_client stradd my_stream
173
174
175 Example:
176
177 Assume you already have an attribute "test" and you'd like to
178 to restrict audio streaming to those files having the "test"
179 attribute set. Define a new stream "only_test" by
180
181 echo 'accept: IS_SET(test)' | para_client stradd only_test
182
183 Then, after switching to the "only_test" stream with
184
185 para_client cs only_test
186
187 only the desired files are going to be streamed.
188
189 There is no need to keep the temporary files containing the stream
190 definition since you can always use the strq command to get it back:
191
192 para_client strq only_test
193
194 The accept/deny expressions are used to find out which songs are
195 permitted. The following four cases are all possible and valid:
196
197 o Neither accept nor deny lines: This selects all songs.
198
199 o Only accept lines: Songs that match at least one accept
200 expression are accepted, all others are denied:
201
202 accept_expr1 or accept_expr2 or ...
203
204 o Only deny lines: Songs that match at least one deny expression are
205 denied, all others are accepted:
206
207 not (deny_expr1 or deny_expr2 ...)
208
209 o Both accept and deny lines: A song is accepted if it matches
210 at least one accept expression, but no deny expression, i.e.
211
212 (accept_expr1 or accept_expr2 or ..) and not
213 (deny_expr1 or deny_expr2 ..)
214
215 The command
216
217 para_client streams
218
219 lists all available streams and
220
221 para_client strdel streamname
222
223 removes the stream "streamname".
224
225 There are more sophisticated ways to define a stream than just using
226 one IS_SET() macro as in the example above. Of course, IS_SET(foo)
227 is true for a given audio file if and only if it has the attribute
228 "foo" set. Here are some more macros you can use:
229
230 o IS_N_SET(attr): True if attribute attr is not set
231
232 o NAME_LIKE(string): True if basename is like (in the sense
233 of mysql) "string"
234
235 o LASTPLAYED(): Expands to number of minutes that are gone
236 since this audio file has been played (by paraslash).
237
238 o NUMPLAYED(): Expands to number of times, the file has
239 been played.
240
241 o PICID(): Expands to the number of the picture which is
242 associated with this song.
243
244 To give a real-life example, suppose you have already added the
245 attributes "pop", "rock" with the "na" command. Assume also that you
246 have set these attributes for some or all of your songs having the
247 corresponding properties.
248
249 If you like to be waked up in the morning by poprock songs, but you
250 have some strange feeling telling you that just a few seconds of
251 Madonna's voice will be enough to mess up your whole day, just write
252 the lines
253
254 accept: IS_SET(pop) and IS_SET(rock)
255 deny: NAME_LIKE(%Madonna%)
256
257 to some temporary file "tmp" and do
258
259 para_client stradd wake < tmp
260
261 You can then switch to the new stream with
262
263 para_client cs wake
264
265 or you can let cron do this for you on a daily basis..
266
267 Accept/deny lines affect only the set of admissible audio files,
268 but not the order in which these are streamed. That's where the score
269 expression comes into play.
270
271 Scoring
272 ~~~~~~~
273 You may put a single score line anywhere in the stream definition. If
274 omitted, the default scoring rule specified in the configuration file
275 applies. If there is no default scoring rule in the config file either,
276 the compiled in default is going to be used (see para_server -h).
277
278 Simple examples of scoring rules (either specified in a stream
279 definition or as the default scoring rule in the config file) include:
280
281 LASTPLAYED()/1440
282
283 This means that the score of an audio file is just the number of days
284 that went by since it has been played the last time (one day is 1440
285 minutes). In other words, the mysql selector choses that admissible
286 file which wasn't played for the longest time.
287
288 However, one disadvantage of this scoring sheme is that new files,
289 once played, are going to be deferred for a possibly very long period
290 depending on the size of your collection of (admissible) files. Hence
291 the following scoring rule comes into mind:
292
293 score: -NUMPLAYED()
294
295 since this gives newer files, i.e. files to which you haven't listen to
296 that often, a higher score than older songs you already know by heart.
297
298 You can also use a combination of these two methods:
299
300 score: LASTPLAYED()/1440 - 10 * NUMPLAYED()
301
302 which subtracts 10 score points for each time paraslash has played
303 this file.
304
305 Another useful feature for scoring is due to the fact that
306 "true" expands to one and "false" to zero. So you can also use the
307 IS_SET/IS_N_SET/NAME_LIKE macros in a score line to give your favorite
308 band "bar" some extra points:
309
310 score: 40 * IS_SET(foo) + 20 * NAME_LIKE(%bar%) + LASTPLAYED()/1440
311
312
313 Pictures
314 ~~~~~~~~
315
316 The mysql selector can also magage images that, when associated
317 with one or more audio files, can be displayed by para_sdl_gui and
318 para_krell. It is also possible to just retrieve the current image via
319
320 para_client pic > filename
321
322 in order to feed it to your favorite tool. Try
323
324 para_client help | grep ^pic
325
326 and read the online help of the shown commands for more information.