Header parameters are typically specified in the URL like this:
http://www.boddie.org.uk/application?param1=value1¶m2=value2
Following the rules set out in "URLs and Paths", we can say that the "query string" employed is this:
param1=value1¶m2=value2
From this string, we may extract the parameters and state that they are the following:
param1
with the value value1
param2
with the value value2
Parameters encoded in this way can be written into hyperlinks and may be
used to remember things as users navigate their way around an application.
Alternatively, a Web form (in HTML) written to use the GET
request method may be used to achieve the same
effect:
<form method="get" action="http://www.boddie.org.uk/application">
<input name="param1" type="text" value="value1" />
<input name="param2" type="text" value="value2" />
</form>
Transaction objects provide the following methods to access parameters specified in request headers. The terminology used in the API describes such parameters as path fields, since such parameters are often provided by form fields.
get_fields_from_path
encoding
parameter may be used to assist
the process of converting parameter values to Unicode objects - see
below for a discussion of the issues with this parameter.get_query_string
There are some limitations with header parameters: