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Readme for analog3.1

Aliases

After analog has read each logfile entry, it then applies aliases to each of the items. First, if you have a case insensitive filesystem, analog converts the filename to lower case. Usually analog assumes that Unix filesystems are case sensitive and other systems are case insensitive. You might want to override its choice, if, for example, you have transferred files from one machine to another, so as to use the convention on the original machine. You can do this by the commands

CASE INSENSITIVE
CASE SENSITIVE

Next it applies built-in aliases to each item. For example, it knows that %7E in a filename or referrer is equivalent to ~ and translates it accordingly. It also strips off the directory suffix from any filenames which have it. This suffix is normally index.html, but you can specify another one instead with a command such as

DIRSUFFIX default.htm

(You can only have one DIRSUFFIX.) There are other built-in aliases for other items: for example, hostnames are converted to lower case at this point.

After this, it applies user-specified aliases to each item. These aliases are useful if, for example, you know that two filenames correspond to the same file, or if you want to translate local hostnames to their internet equivalents. You specify aliases by commands like

FILEALIAS /football.html /soccer.html
HOSTALIAS lion lion.statslab.cam.ac.uk

There is also the special command FILEALIAS none, which cancels any other file aliases which might have been specified.

The alias commands for the other items are called BROWALIAS, REFALIAS, USERALIAS and VHOSTALIAS. Only one alias is ever applied to any item. So after

FILEALIAS /football.html /soccer.html
FILEALIAS /soccer.html /brazil.html

the file /soccer.html would get translated to /brazil.html, but /football.html would only get translated to /soccer.html and would not see the second alias.

You can also use wildcards (? and *) in alias commands. The left hand side can contain at most one *, unless the right hand side contains no *'s. If the right hand side contains a * too, then the part of the name represented by the * on the left hand side will be substituted at the position of the * on the right hand side. So, for example,

FILEALIAS /football/* /soccer/

would translate /football/rules.html to /soccer/, but

FILEALIAS /football/* /soccer/*

would translate /football/rules.html to /soccer/rules.html.

There is another set of alias commands, called output aliases. There is one of these for each of the reports, except the time reports. Instead of acting on items when the logfile is being read, they act on individual lines in the output. So for example, the command

TYPEOUTPUTALIAS .txt ".txt (Plain text files)"

would provide an explanation of that line in the file type report.

There can be some confusion between some ALIAS and OUTPUTALIAS commands. For example, what is the difference between HOSTALIAS and HOSTOUTPUTALIAS? In fact, there are several differences, resulting from the different times at which the aliases are processed. The HOSTALIAS applies to the host items, but the HOSTOUTPUTALIAS only applies to the lines in the host report. This means that the HOSTALIAS also affects the other reports which use the hosts, such as the domain report, whereas the HOSTOUTPUTALIAS only affects the host report. Also the HOSTOUTPUTALIAS applies separately to each line of the host report. This means that if two separate hosts translate to the same thing in a HOSTALIAS command, they will become one host ever after. But if one were to use the same HOSTOUTPUTALIAS commands, there would be two hosts, which would just happen to have the same name in one report.

In summary, HOSTALIAS would normally be used if a single host had two different names, so might otherwise appear to be two hosts, whereas HOSTOUTPUTALIAS would normally be used to annotate or clarify the host report.

The full list of output aliases is REQOUTPUTALIAS, REDIROUTPUTALIAS, FAILOUTPUTALIAS, TYPEOUTPUTALIAS, DIROUTPUTALIAS, HOSTOUTPUTALIAS, DOMOUTPUTALIAS, REFOUTPUTALIAS, REFSITEOUTPUTALIAS, REDIRREFOUTPUTALIAS, FAILREFOUTPUTALIAS, BROWOUTPUTALIAS, FULLBROWOUTPUTALIAS, VHOSTOUTPUTALIAS, USEROUTPUTALIAS and FAILUSEROUTPUTALIAS.

There is one known bug with OUTPUTALIAS. The report is sorted before the OUTPUTALIAS is applied. This means that if the SORTBY for the report is set to ALPHABETICAL, then the report will not be sorted correctly.

Stephen Turner
E-mail: sret1@cam.ac.uk

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