URL Rewrite object

The URL Rewrite object defines friendly URLs, intended to improve the usability and accessibility of a website. 

It lets you define URLs and the corresponding mapping to objects with their parameters.

Defining friendly URLs lets you separate the interface from the implementation:

• It helps you to make it SEO friendly
• The defined URLs are independent of the object names and their modularization in the KB
• The defined URLs are independent of the chosen generator, a feature that adds flexibility and reduces lock-in to a specific generator (.NET, .NET Framework, or Java).

The object has the following parts: 

• Rewrite Rules
• Variables
• Help
• Documentation

Rewrite Rules

This is the main part of a URL Rewrite Object, as it lets you define the mappings (also called rewrite rules).

Each mapping consists of a part on the left where the URL (or part of it) is specified, and on the right side, the object and its parameters are referenced. Mappings are separated by a semicolon.

home                                 => Home; 

core/clients                        => Core.WWClient;
core/clients/{&ClientId}/{&Mode}    => Core.Client(&Mode,&ClientId);
core/clients/{&ClientId}            => Core.ViewClient(&ClientId);

The above mappings result in URLs like the following:

• http://www.example.com/home
• http://www.example.com/core/clients
• http://www.example.com/core/clients/1/UPD
• http://www.example.com/core/client/1

Considerations

• You do not need to reference all the parameters
• Creating a URL Rewrite object changes the behavior of the Link function. Instead of returning document-relative URLs, it returns server-relative URLs when a URL Rewrite object exists. This can introduce breaking changes in your code; for example, if you concatenate the resulting string with another to create an absolute URL.
• API object is not supported.

Restrictions

To use this feature, some restrictions apply

• Parameters can only be mapped on objects where the Encrypt URL parameters property is set to 'No' and if the Parameters Style property for Environments is set to 'Named'.
• The Web User Experience property must be set to 'Smooth' in objects affected by these rules.

Samples

1) Partial parameter references

Missing parameters will be added to the query string:

core/clients/{&ClientId}    => Core.Client(&Mode,&ClientId);

This result is:

http://www.example.com/core/clients/1?Mode=UPD

when the object is called as follows:

Core.Client('UPD',1)

2) Object mapping without parameter mapping

You can write

core/client => Core.Client;

even if the object Core.Client has a

parm(in:&Mode,in:&ClientId)

In this sample, when the parameter style is positional, the resulting URL would be as follows:

http://www.example.com/core/client?UPD,1

when the object is called as follows:

Core.Client('UPD',1)

Deployment

GeneXus automatically deploys all the rules defined in the URL Rewrite objects of the KB when deploying a Deployment Unit object. This implies that there must be no conflict among rules defined in different objects.

Java-specific

When deploying to Tomcat 8 or higher, rewrite rules work automatically; however, when you deploy to another Servlet Server, you may need to make extra configurations. For that, take the rules from the urlrewrite.config file to configure the server.

Scope

Generators: .NET, .NET Framework, Java