I need to extract a variable named “product_code” from a path parameter.
My proxies are configured with a “*” wildcard at the specific path segment where I have my path parameter :
<BasePath>/product_definition/v1/product/*/sales_attributes</BasePath>
The right proxy is called when tested with Postman.
In order to extract the “product_code”, I am using the following ExtractVariable policy in the Proxy Request PreFlow :
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables name="Extract-Product-Code">
<DisplayName>Extract Product Code</DisplayName>
<Source>request</Source>
<URIPath>
<Pattern>/product_definition/*/product/{product_code}</Pattern>
<Pattern>/product_definition/*/product/{product_code}/*</Pattern>
<Pattern>/product_definition/*/product/{product_code}/**</Pattern>
</URIPath>
<VariablePrefix>urirequest</VariablePrefix>
</ExtractVariables>
While looking through the Trace, no variable “product_code” is defined in the context after executing the policy.
Hi Alexis,
If you remove variable prefix element from your policy definition the variables will be shown in trace tool.
This is a short fall of trace tool that it doesn’t display prefixed variables.
Cheers!
No luck,
I tried removing the “VariablePrefix” and / or using a JavaScript policy to print the value, but nothing worked.
Hi @Alexis Brodeur ,
Got the problem.
Extract Variables policy take the URI after your basepath as pattern component. That means it will work on only proxy.pathsuffix elements.
Example:
Proxy basepath : /v1/products
if you make a request like GET /v1/products/12345/sales_attributes
then proxy.pathsuffix will be /12345/sales_attributes and in extract variable you can give pattern as
<Pattern>/{product_code}/sales_attributes</Pattern>
Since in your case the basepath is a generic the proxy path suffix will be empty hence the pattern you gave is not matching anything.
For a better design please make your basepath as /product_definition/v1/product and in extract variables policy give specific path without any * or **.
Example:
for base path /product_definition/v1/product give patterns as below
<Pattern>/{product_code}/sales_attributes</Pattern>
<Pattern>/{product_code}</Pattern>
<Pattern>/{product_code}/sales_attributes/{sale_attribute}</Pattern>
Extract variable policy will match longest path pattern and populate the variables.
Also for checking variables in trace you need to remove
<VariablePrefix>urirequest</VariablePrefix>
Hope this helps
1 Like
hanselm
September 29, 2016, 6:56pm
6
You can also use an AssignMessage policy after the ExtractVariables to confirm the path param is extracted and verify it in the Trace tool when the AM policy executes:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<AssignMessage async="false" continueOnError="false" enabled="true" name="Assign-Message">
<DisplayName>Assign Message</DisplayName>
<Properties/>
<AssignVariable>
<Name>pcode</Name>
<Ref>urirequest.product_code</Ref>
</AssignVariable>
<IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables>
<AssignTo createNew="false" transport="http" type="request"/>
</AssignMessage>
I got it to work with my initial Proxy Endpoint configuration using the following ExtractVariable policy :
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables name="Extract-Product-Code">
<DisplayName>Extract Product Code</DisplayName>
<Variable name="proxy.url">
<Pattern>**/product_definition/*/product/{product_code}/**</Pattern>
<Pattern>**/product_definition/*/product/{product_code}</Pattern>
</Variable>
<IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
</ExtractVariables>
@Mohammed Zuber , I am keeping your answer as accepted because I believe this is more of a hack around the way Apigee works. This solution requires parsing the full URL of the proxy including the protocol and domain, which is why I have to use “**” at the start of my patterns.
1 Like
