fix #71 and #73: add support for outdir template and enhance docs

kleingebaeck.go

@@ -55,6 +55,7 @@ CONFIGURATION
     multiline string surrounded by three double quotes. You can left out
     certain fields and use any formatting you like. Refer to
     <https://pkg.go.dev/text/template> for details how to write a template.
+    Also read the TEMPLATES section below.
 
     If you're on windows and want to customize the output directory, put it
     into single quotes to avoid the backslashes interpreted as escape chars
@@ -62,6 +63,71 @@ CONFIGURATION
 
         outdir = 'C:\Data\Ads'
 
+TEMPLATES
+    Various parts of the configuration can be modified using templates: the
+    output directory, the ad directory and the ad listing itself.
+
+  OUTPUT DIR TEMPLATE
+    The config varialbe "outdir" or the command line parameter "-o" take a
+    template which may contain:
+
+    "{{.Year}}"
+    "{{.Month}}"
+    "{{.Day}}"
+
+    That way you can create a new output directory for every backup run. For
+    example:
+
+        outdir = "/home/backups/ads-{{.Year}}-{{.Month}}-{{.Day}}"
+
+    Or using the command line flag:
+
+        -o "/home/backups/ads-{{.Year}}-{{.Month}}-{{.Day}}"
+
+    The default value is "." - the current directory.
+
+  AD DIRECTORY TEMPLATE
+    The ad directory name can be modified using the following ad values:
+
+    {{.Price}}
+    {{.ID}}
+    {{.Category}}
+    {{.Condition}}
+    {{.Created}}
+    {{.Slug}}
+    {{.Text}}
+
+    It can only be configured in the config file. By default only
+    "{{.Slug}}" is being used, this is the title of the ad in url format.
+
+  AD TEMPLATE
+    The ad listing itself can be modified as well, using the same variables
+    as the ad name template above.
+
+    This is the default template:
+
+        Title: {{.Title}}
+        Price: {{.Price}}
+        Id: {{.ID}}
+        Category: {{.Category}}
+        Condition: {{.Condition}}
+        Created: {{.Created}}
+        Expire: {{.Expire}}
+    
+        {{.Text}}
+
+    The config parameter to modify is "template". See example.conf in the
+    source repository. Please take care, since this is a multiline string.
+    This is how it shall look if you modify it:
+
+        template="""
+        Title: {{.Title}}
+    
+        {{.Text}}
+        """
+
+    That is, the content between the two """ chars is the template.
+
 SETUP
     To setup the tool, you need to lookup your userid on kleinanzeigen.de.
     Go to your ad overview page while NOT being logged in: