I have not been able to find any way to marshall a set of HTTP Post form
parameters AND a file using akka-http, where the form data parameters are
NOT www-url-encoded, but rather each placed in a separate MIME part, with
no Content-Type header. This appears to be the format required in order to
do an HTTP POST to AWS S3 with a policy. Furthermore, it appears AWS/S3 is
not happy with Chunked HTTP POST requests, and therefore I've had to use
toStrict on all my entities. I've resorted to some hacky code, which
works, but I find it surprising that there is no built-in way to generate a
multi-part MIME message where post parameters are not combined into one
www-url-encoded query string.
Here is my (admittedly ugly) code:
val m = Map(
"key" -> "upload/quux.txt",
"acl" -> acl,
"policy" -> policy,
"X-amz-algorithm" -> "AWS4-HMAC-SHA256",
"X-amz-credential" -> s"$awsAccessKeyId/$shortDate/$region/$service
/aws4_request",
"X-amz-date" -> date,
"X-amz-expires" -> expires.toString,
"X-amz-signature" -> signature
)
implicit val timeout: FiniteDuration = 10.seconds
val uri = s"http://$bucket.$service-$region.amazonaws.com";
// create request entities for each of the POST parameters. Note that
generating Strict entities is an asynchronous
// operation (returns a future). Strict entities are NOT chunked. It
appears AWS is not happy with chunked MIME
// body parts.
val strictFormDataEntityFuture = m.map { case (k, v) => (k,
HttpEntity(ContentTypes.NoContentType,
v).toStrict(timeout)) }
val responseFuture = for {
strictEntityMap <- Future.sequence(strictFormDataEntityFuture.map(
entry => entry._2.map(i => (entry._1, i)))).map(_.toMap) recoverWith { case
t: Throwable => throw t }
formDataBodyPartList = strictEntityMap.map {e =>
Multipart.FormData.BodyPart.Strict(e._1, e._2)}.toList
fileEntity <- HttpEntity(ContentTypes.`application/octet-stream`, 3,
Source.single(ByteString("foo"))).toStrict(timeout) recoverWith { case t:
Throwable => throw t }
multipartForm = Multipart.FormData(Source(formDataBodyPartList ++List
(Multipart.FormData.BodyPart("file", fileEntity, Map("filename" -> "foo.bin"
)))))
requestEntity <- Marshal(multipartForm).to[RequestEntity] recoverWith
{ case t: Throwable => throw t }
strictRequestEntity <- requestEntity.toStrict(timeout) recoverWith {
case t: Throwable => throw t }
response <- Http().singleRequest(HttpRequest(method =
HttpMethods.POST, uri = uri, entity = strictRequestEntity)) recoverWith {
case t: Throwable => throw t }
responseEntity <- Unmarshal(response.entity).to[String] recoverWith {
case t: Throwable => throw t }
} yield (responseEntity, response)
If anyone can suggest a better approach, I'd appreciate it. Thanks.
On Sunday, October 11, 2015 at 10:45:37 PM UTC-7, Eric Swenson wrote:
>
> Hey Scott!
>
> When you get a chance, if you can point me to the right one, I'd
> appreciate it. I've been looking at the sources, tests, and examples, and I
> can't find how to do it. What I'm after is a way to take a Form, and emit
> a multi-part MIME message with one part for each field in the form and one
> part for the single file I need to upload. Using code like this:
>
> val formBodyPartFuture = for {
>
> httpEntity <- Marshal(form).to[HttpEntity]
>
> strictEntity <- httpEntity.toStrict(timeout)
>
> } yield Multipart.FormData.BodyPart("foo", strictEntity)
>
>
> gives me one body part with Content-Type x-www-url-encoded, and the set of
> all fields are encoded as in a query string.If you can point me to the
> "other" way of marshalling a form to a set of mime body parts, I'd
> appreciate it. I had pretty much given up (and googling and using stack
> overflow have turned up nothing) and was going to generate the parts
> manually. i'm sure there must be a correct way to do this. Thanks. --
> Eric
>
>
>
>
> On Sunday, October 11, 2015 at 9:43:20 PM UTC-7, Scott Maher wrote:
>>
>> I can't test this as I am not at home but there are multiple form
>> marshallers, one for url encoding and one for multipart called, I think,
>> Multipart.FormData. sorry if you already know this.
>>
>> Hi Eric! :P
>> On Oct 11, 2015 9:18 PM, "Eric Swenson" <er...@swenson.org> wrote:
>>
>>> AWS/S3 HTTP Post with a policy requires an HTTP post with multipart-mime
>>> -- one part for the file and one part, each, for various form parameters.
>>> When I use akka.http and attempt to marshal FormData to an Entity and use
>>> that to create a multi-part mime message, all the form data go into one
>>> mime-part using the query string format (foo=bar&baz=quux). AWS rejects
>>> such a request as it doesn't want all form parameters in a single
>>> www-url-encoded-form-data part, but rather separate mime parts for each
>>> parameter. How to I cause a Form to be martialled in this way using
>>> akka.http?
>>>
>>> --
>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>> >>>>>>>>>> Check the FAQ:
>>> http://doc.akka.io/docs/akka/current/additional/faq.html
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>>
--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ:
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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