Added a custom key function in server side

README.md

@@ -81,8 +81,22 @@ An example using it within an Om component:
     )
 ```
 
+The `uploaded` channel will return a map with the `:file` object that
+was uploaded and a `:response` map that contains the `:location`,
+`:bucket`, `:key`, and `:etag` of the file in S3. 
+
 ## Changes
 
+#### Not Released
+
+- Added the `:key-fn` option `s3-beam.handler/sign-upload` to generate
+  custom S3 keys from `file-name` and `mime-type`.
+- **Breaking Change**: the `uploaded` channel now returns a map with
+  the `:file` that was uploaded and the S3 `:response` map with itself
+  contains all the information necessary to locate the file in S3:
+  `:location`, `:key`, `:bucket`, and `:etag` instead of just the
+  location as a string.
+
 #### 0.3.0
 
 -  Allow customization of server-side endpoint ([1cb9b27](https://github.com/martinklepsch/s3-beam/commit/1cb9b2703691e172e275a95490b3fc8209dfa409))
@@ -91,7 +105,7 @@ An example using it within an Om component:
 
 #### 0.2.0
 
-- Allow passing of `aws-zone` parameter to `s3-sign` handler function ([b880736](https://github.com/martinklepsch/s3-beam/commit/b88073646b7c92b5493a168ce25d27feaa130c9e))
+- Allow passing of `aws-zone` parameter to `s3-sign` handler function. ([b880736](https://github.com/martinklepsch/s3-beam/commit/b88073646b7c92b5493a168ce25d27feaa130c9e))
 
 ## Contributing
 

src/clj/s3_beam/handler.clj

@@ -34,17 +34,34 @@
                (.init (javax.crypto.spec.SecretKeySpec. (.getBytes key) "HmacSHA1")))
              (.getBytes string "UTF-8"))))
 
-(defn sign-upload [{:keys [file-name mime-type]}
-                   {:keys [bucket aws-zone aws-access-key aws-secret-key]}]
-  (let [p (policy bucket file-name mime-type)]
-    {:action (str "https://" bucket "." aws-zone ".amazonaws.com/")
-     :key    file-name
-     :Content-Type mime-type
-     :policy p
-     :acl    "public-read"
-     :success_action_status "201"
-     :AWSAccessKeyId aws-access-key
-     :signature (hmac-sha1 aws-secret-key p)}))
+(defn sign-upload
+  "Takes the request's params {:file-name :mime-type} and
+  the aws-config {:bucket, :aws-zone, :aws-access-key, :aws-secret-key}
+  to produce a map with all the data needed to upload to s3.
+  May take an extra opts map with:
+   :key-fn - A fn (ifn?) that takes the request params {:file-name :mime-type}
+             and returns the key for S3 (i.e. hash of the file-name, UUID, etc.).
+             It should be side-effect free and return a string. 
+             Defaults to the :file-name keyword."
+  ([params aws-config] (sign-upload params aws-config {:key-fn :file-name}))
+  ([{:keys [file-name mime-type] :as params}
+    {:keys [bucket aws-zone aws-access-key aws-secret-key]}
+    {:keys [key-fn]}]
+   {:pre [(ifn? key-fn)]}
+   (let [key (key-fn params)]
+     (assert (string? key)
+       (str "The given :key-fn returned " key " with type " (type key)
+         " when given file-name: " file-name
+         " and mime-type: " mime-type ". It should return a string."))
+     (let [p (policy bucket key mime-type)]
+       {:action (str "https://" bucket "." aws-zone ".amazonaws.com/")
+        :key    key 
+        :Content-Type mime-type
+        :policy p
+        :acl    "public-read"
+        :success_action_status "201"
+        :AWSAccessKeyId aws-access-key
+        :signature (hmac-sha1 aws-secret-key p)}))))
 
 (defn s3-sign [bucket aws-zone access-key secret-key]
   (fn [request]

src/cljs/s3_beam/client.cljs

@@ -31,16 +31,33 @@
       (.append fd (name k) v))
     fd))
 
-(defn upload-file [upload-info ch]
+(defn xml->clj
+  "Transforms a shallow XML document into an idiomatic clj map"
+  [xml]
+  (let [kv (->> (array-seq (.. xml -firstChild -childNodes))
+                (map (fn [n] [(.toLowerCase (.-nodeName n))
+                             (gdom/getTextContent n)])))]
+    (zipmap (map (comp keyword first) kv) (map second kv))))
+
+(defn upload-file
+  "Uploads the file given by upload-info and puts the file and
+  upload response in the ch. Contains the following keys:
+    :file - the File Object that was uploaded
+    :response - S3 file data
+      :key
+      :location
+      :bucket
+      :etag"
+  [upload-info ch]
   (let [sig-fields [:key :Content-Type :success_action_status :policy :AWSAccessKeyId :signature :acl]
         signature  (select-keys (:signature upload-info) sig-fields)
         form-data  (formdata-from-map (merge signature {:file (:f upload-info)}))]
     (xhr/send
      (:action (:signature upload-info))
      (fn [res]
-       (let [loc (aget (.getElementsByTagName (.getResponseXml (.-target res)) "Location") 0)]
-         (put! ch (gdom/getTextContent loc))
-         (close! ch)))
+       (put! ch {:file (:f upload-info)
+                 :response (xml->clj (.. res -target getResponseXml))})
+       (close! ch))
      "POST"
      form-data)))