URL Rewrite Handler
The URL Rewrite handler can be used to proxy and rewrite requests to a different API without writing any code. The handler allows mapping request data and parameters to a URL on another host. You can also combine the URL rewrite handler with policies such as the Change Method Inbound policy to modify virtually any aspect of your request.
Setup via Portal
The Rewrite Handler can be added to any route using the Route Designer. Open the Route Designer by navigating to the Code Editor tab then clicking routes.json. Inside of any route, select URL Rewrite from the Request Handlers drop down.
In the text box enter the URL to rewrite the request. Values can be mixed into the URL string using Javascript string interpolation syntax. For example:
https://echo.zuplo.io/${method}/${params.productId}
The following objects are available for substitution:
request: ZuploRequest
- the fullZuploRequest
objectparams: Record<string, string>
- The parameters of the route. For example,params.productId
would be the value of:productId
in a route.query: Record<string, string>
- The query parameters of the route. For example,query.filterBy
would be the value of?filterBy=VALUE
.headers: Headers
- the incoming request's headers objecturl: string
- The full incoming request as a stringhost: string
- Thehost
portion of the incoming urlhostname: string
- Thehostname
portion of the incoming urlpathname: string
- Thepathname
portion of the incoming urlport: string
- Theport
portion of the incoming urlsearch
- Thesearch
portion of the incoming url
Use the following methods to encode portions of the URL:
encodeURIComponent
: TheencodeURIComponent()
function encodes a URI by replacing each instance of certain characters with escape sequences.e
: An alias toencodeURIComponent
to help keep urls more readable. Can be used like${e(params.productId)}
Example Values
A few examples of the values of various substitutions.
${headers.get("content-type")}
-"application/json"
${host}
-"example.com:8080"
${hostname}
-"example.com"
${method}
-"GET"
${origin}
-"https://example.com"
${params.productId}
-":productId"
${pathname}
-"/v1/products/:productId"
${port}
-"8080"
${protocol}
-"https:"
${query.category}
-"cars"
${search}
-"?category=cars"
${url}
-"https://example.com:8080/v1/products/:productId?category=cars"
Setup via Routes.json
The URL Rewrite handler can also be added manually to the routes.json file with the following route configuration.
{
"label": "Welcome",
"path": "/",
"methods": ["GET"],
"handler": {
"module": "$import(@zuplo/runtime)",
"export": "urlRewriteHandler",
"options": {
"rewritePattern": "https://welcome.zuplo.io"
}
},
"corsPolicy": "anything-goes",
"version": "none",
"summary": "Proxy Welcome API",
"description": "This Route will proxy the welcome.zuplo.io api"
}