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relatively simple?
Here is some JS that behaves this way:
var urlRe = new RegExp('(https?)://([^/]+)/?');
function resolveUrl(originalUrl, newUrl) {
if (newUrl.startsWith("/")) {
// relative URL
var match = urlRe.exec(originalUrl);
if ( ! match) { return newUrl; }
return match[1] + '://' + match[2] + newUrl;
}
return newUrl;
}
function log(str) {
var time = (new Date()).toString();
print('[' + time.substr(11, 4) + '-' +
time.substr(4, 3) + '-' + time.substr(8, 2) + ' ' +
time.substr(16, 8) + '] ' + str );
}
function invokeTargetFollowRedirects(targetUrl, count, indent) {
count = count || 0;
indent = indent || '';
var headers = { };
log(indent+ "GET " + targetUrl);
var request = new Request(targetUrl, 'GET', headers);
var exchange = httpClient.send(request);
exchange.waitForComplete();
if (exchange.isSuccess()) {
log(indent + " ==> Success");
var response = exchange.getResponse();
if (response.status.code == 302 || response.status.code == 301) {
var newLocation = response.headers['Location'] + '';
if (newLocation != 'undefined') {
log(indent + " Redirect " + newLocation);
newLocation = resolveUrl(targetUrl, newLocation);
log(indent + " Resolved to: " + newLocation);
return invokeTargetFollowRedirects(newLocation, count + 1, indent + ' ');
}
else {
return {error: false, redirectCount: count, status: response.status };
}
}
else {
return {error: false, redirectCount: count, status: response.status };
}
}
else {
return {error: true, redirectCount: count, status: 0 };
}
}
var targetUrl = (new MessageTemplate(properties.target)).fill();
var response = invokeTargetFollowRedirects(targetUrl);
context.setVariable('final_response', JSON.stringify(response));
It could be simpler. A significant portion of the code there (the count, the indent, the log function) is used only for diagnostics, to show it working. If you use this in production, you will want to eliminate that stuff. and also I guess modify the function so that it returns the response of the final call. (including payload and status).
I used that code on an example target and the output was like this:
To use that you need a JS policy configured like this:
<Javascript name='JS-InvokeTargetAndFollow' timeLimit='3200' >
<Properties>
<Property name='target'>https://example.com/will-redirect</Property>
</Properties>
<IncludeURL>jsc://messageTemplate.js</IncludeURL>
<ResourceURL>jsc://invokeTargetAndFollow.js</ResourceURL>
</Javascript>
The timeLimit needs to be high enough to allow for *all* the redirects.
I used that messageTemplate thing to allow the target to be specified with a variable reference, like this:
<Javascript name='JS-InvokeTargetAndFollow' timeLimit='3200' >
<Properties>
<Property name='target'>{my_desired_target_url}</Property>
</Properties>
<IncludeURL>jsc://messageTemplate.js</IncludeURL>
<ResourceURL>jsc://invokeTargetAndFollow.js</ResourceURL>
</Javascript>But if you don't need that, you can omit the MessageTemplate.
Attached please find a working example API Proxy.
