Response.redirected - Web APIs 编辑

The read-only redirected property of the Response interface indicates whether or not the response is the result of a request you made which was redirected.

Relying on redirected to filter out redirects makes it easy for a forged redirect to prevent your content from working as expected. Instead, you should actually instead do the filtering when you call fetch(). See the example Disallowing redirects, which shows this being done.

Syntax

var isRedirected = Response.redirected;

Value

A Boolean which is true if the response indicates that your request was redirected.

Examples

Detecting redirects

Checking to see if the response comes from a redirected request is as simple as checking this flag on the Response object. In the code below, a textual message is inserted into an element when a redirect occurred during the fetch operation. Note, however, that this isn't as safe as outright rejecting redirects if they're unexpected, as described under Disallowing redirects below.

fetch("awesome-picture.jpg").then(function(response) {
  let elem = document.getElementById("warning-message-box");
  if (response.redirected) {
    elem.innerHTML = "Unexpected redirect";
  } else {
    elem.innerHTML = "";
  }
  return response.blob();
}).then(function(imageBlob) {
  let imgObjectURL = URL.createObjectURL(imageBlob);
  document.getElementById("img-element-id").src = imgObjectURL;
});

Disallowing redirects

Because using redirected to manually filter out redirects can allow forgery of redirects, you should instead set the redirect mode to "error" in the init parameter when calling fetch(), like this:

fetch("awesome-picture.jpg", { redirect: "error" }).then(function(response) {
  return response.blob();
}).then(function(imageBlob) {
  let imgObjectURL = URL.createObjectURL(imageBlob);
  document.getElementById("img-element-id").src = imgObjectURL;
});

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Fetch API
• ServiceWorker API
• HTTP access control (CORS)
• HTTP