Multiplex akka streams source into two copies
I'm trying to cache a streaming source to disk while I'm also sending it out as an HttpResponse, i.e. I have a Source[ByteString,_] that I want to hand to HttpEntity, but I also want to run the same data into a FileIO.toPath sink.
|-> FileIO.toPath
Source[ByteString,_] ->|
|-> HttpEntity(contentType, Source[ByteString,_]
It seems that Broadcast is what I should use for fan-out but from the description, it writes to two sinks and while FileIO.toPath is a sink, HttpEntity expects a Source.
There's also Source.fromGraph which looks like it would create a source from a GraphStage, such as a Broadcast stage, but I can't quite figure out how I would get the FileIO sink in there.
scala akka-stream akka-http
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
add a comment |
I'm trying to cache a streaming source to disk while I'm also sending it out as an HttpResponse, i.e. I have a Source[ByteString,_] that I want to hand to HttpEntity, but I also want to run the same data into a FileIO.toPath sink.
|-> FileIO.toPath
Source[ByteString,_] ->|
|-> HttpEntity(contentType, Source[ByteString,_]
It seems that Broadcast is what I should use for fan-out but from the description, it writes to two sinks and while FileIO.toPath is a sink, HttpEntity expects a Source.
There's also Source.fromGraph which looks like it would create a source from a GraphStage, such as a Broadcast stage, but I can't quite figure out how I would get the FileIO sink in there.
scala akka-stream akka-http
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
can you just have one source -> sink for FileIO.toPath and pass source to HttyEntity directly?
– tomcy
Nov 22 '18 at 6:45
From my experiments, using the source twice runs the source twice, i.e. i'm downloading the source twice rather than multiplexing the single download
– Arne Claassen
Nov 22 '18 at 18:40
I don't think its achievable because when your HttpEntity takes Source as part of its parameter, it will call run() eventually and at that point your source will be triggered second time.
– tomcy
Nov 22 '18 at 22:48
add a comment |
I'm trying to cache a streaming source to disk while I'm also sending it out as an HttpResponse, i.e. I have a Source[ByteString,_] that I want to hand to HttpEntity, but I also want to run the same data into a FileIO.toPath sink.
|-> FileIO.toPath
Source[ByteString,_] ->|
|-> HttpEntity(contentType, Source[ByteString,_]
It seems that Broadcast is what I should use for fan-out but from the description, it writes to two sinks and while FileIO.toPath is a sink, HttpEntity expects a Source.
There's also Source.fromGraph which looks like it would create a source from a GraphStage, such as a Broadcast stage, but I can't quite figure out how I would get the FileIO sink in there.
scala akka-stream akka-http
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
I'm trying to cache a streaming source to disk while I'm also sending it out as an HttpResponse, i.e. I have a Source[ByteString,_] that I want to hand to HttpEntity, but I also want to run the same data into a FileIO.toPath sink.
|-> FileIO.toPath
Source[ByteString,_] ->|
|-> HttpEntity(contentType, Source[ByteString,_]
It seems that Broadcast is what I should use for fan-out but from the description, it writes to two sinks and while FileIO.toPath is a sink, HttpEntity expects a Source.
There's also Source.fromGraph which looks like it would create a source from a GraphStage, such as a Broadcast stage, but I can't quite figure out how I would get the FileIO sink in there.
scala akka-stream akka-http
scala akka-stream akka-http
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
asked Nov 22 '18 at 4:07
Arne ClaassenArne Claassen
9,03834982
9,03834982
can you just have one source -> sink for FileIO.toPath and pass source to HttyEntity directly?
– tomcy
Nov 22 '18 at 6:45
From my experiments, using the source twice runs the source twice, i.e. i'm downloading the source twice rather than multiplexing the single download
– Arne Claassen
Nov 22 '18 at 18:40
I don't think its achievable because when your HttpEntity takes Source as part of its parameter, it will call run() eventually and at that point your source will be triggered second time.
– tomcy
Nov 22 '18 at 22:48
add a comment |
can you just have one source -> sink for FileIO.toPath and pass source to HttyEntity directly?
– tomcy
Nov 22 '18 at 6:45
From my experiments, using the source twice runs the source twice, i.e. i'm downloading the source twice rather than multiplexing the single download
– Arne Claassen
Nov 22 '18 at 18:40
I don't think its achievable because when your HttpEntity takes Source as part of its parameter, it will call run() eventually and at that point your source will be triggered second time.
– tomcy
Nov 22 '18 at 22:48
can you just have one source -> sink for FileIO.toPath and pass source to HttyEntity directly?
– tomcy
Nov 22 '18 at 6:45
can you just have one source -> sink for FileIO.toPath and pass source to HttyEntity directly?
– tomcy
Nov 22 '18 at 6:45
From my experiments, using the source twice runs the source twice, i.e. i'm downloading the source twice rather than multiplexing the single download
– Arne Claassen
Nov 22 '18 at 18:40
From my experiments, using the source twice runs the source twice, i.e. i'm downloading the source twice rather than multiplexing the single download
– Arne Claassen
Nov 22 '18 at 18:40
I don't think its achievable because when your HttpEntity takes Source as part of its parameter, it will call run() eventually and at that point your source will be triggered second time.
– tomcy
Nov 22 '18 at 22:48
I don't think its achievable because when your HttpEntity takes Source as part of its parameter, it will call run() eventually and at that point your source will be triggered second time.
– tomcy
Nov 22 '18 at 22:48
add a comment |
1 Answer
1
active
oldest
votes
You can use alsoTo:
val originalSource: Source[ByteString, _] = ???
val cachedSource: Source[ByteString, _] = originalSource.alsoTo(FileIO.toPath(/*...*/))
val entity = HttpEntity(contentType, cachedSource)
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53423746%2fmultiplex-akka-streams-source-into-two-copies%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can use alsoTo:
val originalSource: Source[ByteString, _] = ???
val cachedSource: Source[ByteString, _] = originalSource.alsoTo(FileIO.toPath(/*...*/))
val entity = HttpEntity(contentType, cachedSource)
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
add a comment |
You can use alsoTo:
val originalSource: Source[ByteString, _] = ???
val cachedSource: Source[ByteString, _] = originalSource.alsoTo(FileIO.toPath(/*...*/))
val entity = HttpEntity(contentType, cachedSource)
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
add a comment |
You can use alsoTo:
val originalSource: Source[ByteString, _] = ???
val cachedSource: Source[ByteString, _] = originalSource.alsoTo(FileIO.toPath(/*...*/))
val entity = HttpEntity(contentType, cachedSource)
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
You can use alsoTo:
val originalSource: Source[ByteString, _] = ???
val cachedSource: Source[ByteString, _] = originalSource.alsoTo(FileIO.toPath(/*...*/))
val entity = HttpEntity(contentType, cachedSource)
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
answered Nov 23 '18 at 2:34
Jeffrey ChungJeffrey Chung
13.8k62140
13.8k62140
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
add a comment |
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
I started going down that road and it certainly is an answer to my question, unfortunately that did raise more questions: stackoverflow.com/questions/53437098/…
– Arne Claassen
Nov 23 '18 at 6:43
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53423746%2fmultiplex-akka-streams-source-into-two-copies%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
can you just have one source -> sink for FileIO.toPath and pass source to HttyEntity directly?
– tomcy
Nov 22 '18 at 6:45
From my experiments, using the source twice runs the source twice, i.e. i'm downloading the source twice rather than multiplexing the single download
– Arne Claassen
Nov 22 '18 at 18:40
I don't think its achievable because when your HttpEntity takes Source as part of its parameter, it will call run() eventually and at that point your source will be triggered second time.
– tomcy
Nov 22 '18 at 22:48