<HR>
<H2><A NAME="s5">5. Filtering (Old Style upto v1.44)</A></H2>
-<P>Filters can be set for spots, announcements and WWV. You will find the directories for these under /spider/filter. You will
-find some examples in the directories with the suffix <EM>.issue</EM>. There are two types of filter, one for incoming
-information and one for outgoing information. Outgoing filters are in the form <EM>CALLSIGN.pl</EM> and incoming filters
-are in the form <EM>in_CALLSIGN.pl</EM>. Filters can be set for both nodes and users.
-<P>
-<P>All filters work in basically the same way. There are several elements delimited by commas.
-There can be many lines in the filter and they are read from the top by the program.
-When writing a filter you need to think carefully about just what you want to achieve. You
-are either going to write a filter to <EM>accept</EM> or to <EM>reject</EM>.
-Think of a filter as having 2 main elements. For a reject filter, you would have a line
-or multiple lines rejecting the things you do not wish to receive and then a default
-line accepting everything else that is not included in the filter. Likewise, for an
-accept filter, you would have a line or multiple lines accepting the things you wish
-to receive and a default line rejecting everthing else.
+<P>Filters can be set for spots, announcements and WWV. You will find the
+directories for these under /spider/filter. You will find some examples in
+the directories with the suffix <EM>.issue</EM>. There are two types of
+filter, one for incoming information and one for outgoing information.
+Outgoing filters are in the form <EM>CALLSIGN.pl</EM> and incoming filters
+are in the form <EM>in_CALLSIGN.pl</EM>. Filters can be set for both nodes
+and users.
+<P>
+<P>All filters work in basically the same way. There are several elements
+delimited by commas. There can be many lines in the filter and they are
+read from the top by the program. When writing a filter you need to think
+carefully about just what you want to achieve. You are either going to write
+a filter to <EM>accept</EM> or to <EM>reject</EM>. Think of a filter as
+having 2 main elements. For a reject filter, you would have a line or multiple
+lines rejecting the things you do not wish to receive and then a default line
+accepting everything else that is not included in the filter. Likewise, for an
+accept filter, you would have a line or multiple lines accepting the things you
+wish to receive and a default line rejecting everthing else.
<P>
<P>In the example below, a user requires a filter that would only return SSB spots
-posted in Europe on the HF bands. This is achieved by first rejecting the CW section
-of each HF band and rejecting all of VHF, UHF etc based on frequency.
+posted in Europe on the HF bands. This is achieved by first rejecting the CW
+section of each HF band and rejecting all of VHF, UHF etc based on frequency.
Secondly, a filter rule is set based on CQ zones to only accept spots posted in
Europe. Lastly, a default filter rule is set to reject anything outside the filter.
<P>
</PRE>
</CODE></BLOCKQUOTE>
<P>
-<P>The actual elements of each filter are described more fully in the following sections.
+<P>The actual elements of each filter are described more fully in the following
+sections.
<P>
<H2><A NAME="ss5.1">5.1 Spots</A>
</H2>
</PRE>
</CODE></BLOCKQUOTE>
<P>
-<P>There are 3 elements here to look at. Firstly, the action element. This is very simple and only 2 possible states exist,
-accept (1) or drop (0).
+<P>There are 3 elements here to look at. Firstly, the action element. This is
+very simple and only 2 possible states exist, accept (1) or drop (0).
<P>
-<P>The second element is the field_no. There are 13 possiblities to choose from here ....
+<P>The second element is the field_no. There are 13 possiblities to choose from
+here ....
<P>
<BLOCKQUOTE><CODE>
<PRE>
</PRE>
</CODE></BLOCKQUOTE>
<P>
-<P>The third element tells us what to expect in the fourth element. There are 4 possibilities ....
+<P>The third element tells us what to expect in the fourth element. There are
+4 possibilities ....
<P>
<BLOCKQUOTE><CODE>
<PRE>
n - numeric list of numbers e.g. [ 1,2,3 ]
- r - ranges of pairs of numbers e.g. between 2 and 4 or 10 to 17 - [ 2,4, 10,17 ]
+ r - ranges of pairs of numbers e.g. between 2 and 4 or 10 to 17 - [ 2,4, 10,17 ]
a - an alphanumeric regex
d - the default rule
</PRE>
</CODE></BLOCKQUOTE>
<P>
-<P>The fifth element is simply the hops to set in this filter. This would only be used if the filter was for a node of
-course and overrides the hop count in hop_table.pl.
+<P>The fifth element is simply the hops to set in this filter. This would only
+be used if the filter was for a node of course and overrides the hop count in
+hop_table.pl.
<P>
-<P>So, let's look at an example spot filter. It does not matter in the example who the filter is to be used for.
-So, what do we need in the filter? We need to filter the spots the user/node requires and also set a default rule for
-anything else outside the filter. Below is a simple filter that stops spots arriving from outside Europe.
+<P>So, let's look at an example spot filter. It does not matter in the example
+who the filter is to be used for. So, what do we need in the filter? We need
+to filter the spots the user/node requires and also set a default rule for
+anything else outside the filter. Below is a simple filter that stops spots
+arriving from outside Europe.
<P>
<BLOCKQUOTE><CODE>
<PRE>
</PRE>
</CODE></BLOCKQUOTE>
<P>
-<P>So the filter is wrapped in between a pair of square brackets. This tells Spider to look in between these limits.
-Then each line is contained within its own square brackets and ends with a comma. Lets look carefully at the first line.
-The first element is 0 (drop). Therefore anything we put on this line will not be accepted. The next element is 4.
-This means we are filtering by the spotter. The third element is the letter "a" which tells the program to expect an
-alphanumeric expression in the fourth element. The fourth element is a list of letters separated by the pipe symbol.
+<P>So the filter is wrapped in between a pair of square brackets. This tells
+Spider to look in between these limits. Then each line is contained within
+its own square brackets and ends with a comma. Lets look carefully at the first
+line. The first element is 0 (drop). Therefore anything we put on this line
+will not be accepted. The next element is 4. This means we are filtering by
+the spotter. The third element is the letter "a" which tells the program to
+expect an alphanumeric expression in the fourth element. The fourth element
+is a list of letters separated by the pipe symbol.
<P>
-<P>What this line does is tell the program to drop any spots posted by anyone in the USA, Canada or Japan.
+<P>What this line does is tell the program to drop any spots posted by anyone in
+the USA, Canada or Japan.
<P>
-<P>The second line is the default rule for anything else. The "d" tells us this and the line simply reads... accept anything else.
+<P>The second line is the default rule for anything else. The "d" tells us this
+and the line simply reads... accept anything else.
<P>
-<P>You can add as many lines as you need to complete the filter but if there are several lines of the same type it is neater
-to enclose them all as one line. An example of this is where specific bands are set. We could write this like this ....
+<P>You can add as many lines as you need to complete the filter but if there are
+several lines of the same type it is neater to enclose them all as one line.
+An example of this is where specific bands are set. We could write this like
+this ....
<P>
<BLOCKQUOTE><CODE>
<PRE>
];
</PRE>
</CODE></BLOCKQUOTE>
-<P>In this example, only the prefixes listed will be allowed. It is possible to be quite specific. The Dutch prefix "P" is
-followed by several secondary identifiers which are allowed. So, in the example, "PA" or "PE" would be ok but not "PG". It
-is even possible to allow information from a single callsign. In the example this is DK0WCY, to allow the posting of his
-Aurora Beacon.
+<P>In this example, only the prefixes listed will be allowed. It is possible to
+be quite specific. The Dutch prefix "P" is followed by several secondary
+identifiers which are allowed. So, in the example, "PA" or "PE" would be ok
+but not "PG". It is even possible to allow information from a single callsign.
+In the example this is DK0WCY, to allow the posting of his Aurora Beacon.
<P>
<H2><A NAME="ss5.3">5.3 WWV</A>
</H2>
</PRE>
</CODE></BLOCKQUOTE>
<P>
-<P>It should be noted that the filter will start to be used only once a user/node has logged out and back in again.
-<P>I am not going to spend any more time on these filters now as they will become more "comprehensive" in the near future.
+<P>It should be noted that the filter will start to be used only once a user/node
+has logged out and back in again.
+<P>I am not going to spend any more time on these filters now as they will become
+more "comprehensive" in the near future.
<P>
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