s3-beamer

s3-beamer is a Clojure/Clojurescript library designed to help you upload files from the browser to S3 (CORS upload). This library supports all s3 regions (using AWS auth V4).

[whamtet/s3-beamer "0.6.0-SNAPSHOT"] ;; latest release

Usage

To upload files directly to S3 you need to send special request parameters that are based on your AWS credentials, the file name, mime type, date etc. Since we don't want to store our credentials in the client these parameters need to be generated on the server side. For this reason this library consists of two parts:

1. A pluggable route that will send back the required parameters for a given file-name & mime-type
2. A client-side ajax wrapper that will retrieve the special parameters for a given File object, upload it to S3 and report back to you

1. Enable CORS on your S3 bucket

Please follow Amazon's official documentation. An example permission document is

<CORSConfiguration>
 <CORSRule>
   <AllowedOrigin>http://www.example1.com</AllowedOrigin>

   <AllowedMethod>PUT</AllowedMethod>
   <AllowedMethod>POST</AllowedMethod>
   <AllowedMethod>DELETE</AllowedMethod>

   <AllowedHeader>*</AllowedHeader>
 </CORSRule>
 </CORSConfiguration>

2. Plug-in the route to sign uploads

(ns your.server
  (:require [s3-beamer.handler :as s3b]
            [compojure.core :refer [GET defroutes]]
            [compojure.route :refer [resources]]))

(def bucket "your-bucket")
(def aws-zone "eu-west-1")
(def access-key "your-aws-access-key")
(def secret-key "your-aws-secret-key")

(defroutes routes
  (resources "/")
  (GET "/sign" {params :params} (s3b/s3-sign
                                  params
                                  {:bucket bucket
                                   :aws-zone aws-zone
                                   :aws-access-key access-key
                                   :aws-secret-key secret-key})))

If you want to use a route different than /sign, define it in the handler, (GET "/my-cool-route" ...), and then pass it in the options map to upload in the frontend.

If you are serving your S3 bucket with CloudFront, or another CDN/proxy, you can pass upload-url as a fifth parameter to s3-sign, so that the ClojureScript client is directed to upload through this bucket. You still need to pass the bucket name, as the policy that is created and signed is based on the bucket name.

3. Integrate the upload pipeline into your frontend

(ns my-ns
  (:require [s3-beamer.client :as s3]))

(s3/upload
  {:server-url "/sign"
   :sign-params {"my_param" "my_value"}
   :file file
   :success-fn success-fn
   :error-fn error-fn
   :upload-listener upload-listener
   :xhr-handler xhr-handler
   })

• :server-url is the route defined in step 2. Defaults to "/sign" if not provided
• :sign-params includes additional get parameters that will be passed to :server-url.
• :file should be the file object obtained from a file input selector
• :upload-listener will recieve partial upload events (useful for large files)
• :xhr-handler will recieve the file upload xhr object immediately before the file is sent

Please include jQuery on the frontend.