added headers argument to cacheKeyFn to enable using headers as part …

…of the cache key (#59)

CHANGELOG.md

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+# 5.5.0
+
+* Added a third argument to `cacheKeyFn` containing the headers to enable using headers as part
+  of the cache key.
+* Removed unused `url` param from `handleRedirect`.
+
 # 5.4.2
 * Ignore .DS_Store and document fetch retry and timeout config in README.
 * Bump deps to fix security audit.

README.md

@@ -119,7 +119,7 @@ Note: these options are used for the `fetchBuilder`, not the `fetch`-function
 
 * `agent`: (default: null), keepAlive Agent instance.
 * `cache`: (default: `an instance of AsyncCache`) (https://github.com/ExpressenAB/exp-asynccache). To disable caching set `{cache: null}`
-* `cacheKeyFn`: (default: caches on the url + sha1 of the body) An optional formatting function for finding the cache-key. One might, for example, want to cache on an url with the get params stripped.
+* `cacheKeyFn`: (default: caches on the url + sha1 of the body) An optional formatting function for finding the cache-key. One might, for example, want to cache on an url with the get params stripped or use some headers as part of the cache key.
 * `cacheNotFound`: (default: false). If set it will cache 404s, if given a number it will cache the 404 for that time. If the `maxAgeFn` is given, it will get this time as the first parameter.
 * `cacheValueFn`: (default: caches the response body) An optional function for change what will be returned and cached from fetch.
 * `clone`: (default: true), should fetch clone objects before handing them from the cache.

index.js

@@ -167,7 +167,7 @@ function buildFetch(behavior) {
   }
 
   function performRequest(url, headers, explicitTimeout, method, body, redirectCount, callback, onRequestInit) {
-    const cacheKey = cacheKeyFn(url, body);
+    const cacheKey = cacheKeyFn(url, body, headers);
     const startTime = new Date().getTime();
     stats.calls++;
     cache.lookup(cacheKey, (resolveFunction) => {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "exp-fetch",
-  "version": "5.4.3",
+  "version": "5.5.0",
   "description": "A small pluggable fetch lib",
   "main": "index.js",
   "scripts": {

test/fetchingTest.js

@@ -2,6 +2,7 @@
 
 const nock = require("nock");
 const fetchBuilder = require("../.");
+const crypto = require("crypto");
 
 describe("fetch", () => {
   const host = "http://example.com";
@@ -452,6 +453,27 @@ describe("fetch", () => {
       }, done);
     });
 
+    it("should cache with a lookup function using the headers", (done) => {
+      fake.get(path).matchHeader("foo", "foo").reply(200, { some: "content" }, { "cache-control": "max-age=30" });
+      fake.get(path).matchHeader("foo", "foo2").reply(200, { some: "content2" }, { "cache-control": "max-age=30" });
+      function cacheKeyFn(url, body, headers) {
+        const cacheKey = crypto.createHash("md5").update(`${url} ${headers.foo}`).digest("hex");
+        return cacheKey;
+      }
+
+      const fetch = fetchBuilder({ cacheKeyFn }).fetch;
+      Promise.all([
+        fetch({ url: host + path, headers: { foo: "foo" } }),
+        fetch({ url: host + path, headers: { foo: "foo2" } }),
+        fetch({ url: host + path, headers: { foo: "foo2" } }),
+        fetch({ url: host + path, headers: { foo: "foo" } }),
+      ]).then((result) => {
+        expect(result[0]).to.deep.equal({ some: "content" }).eql(result[3]);
+        expect(result[1]).to.deep.equal({ some: "content2" }).eql(result[2]);
+        done();
+      }, done);
+    });
+
     it("should cache with a custom value function", (done) => {
       fake.get(path).reply(200, { some: "content" }, { "cache-control": "max-age=30" });
       const valueFn = function (body, headers, statusCode) {