I want to send a video file from a server written in java to a web browser client.
The socket connection works fine and I have no trouble sending text.
The library I'm using to make a socket server is this https://github.com/TooTallNate/Java-WebSocket
This is the code for sending the file
public void sendFile(WebSocket conn,String path)
{
try
{
File file = new File(path);
byte[] data = new byte[(int)file.length()];
DataInputStream stream = new DataInputStream(new FileInputStream(file));
stream.readFully(data);
stream.close();
conn.send(data);
..snip catch statements..
Here is my javascript code for catching the file
function connect()
{
conn = new WebSocket('ws://localhost:8887');
conn.onopen = function(){alert("Connection Open");};
conn.onmessage = function(evt){if(evt.data instanceof Blob){readFile(evt);}else{alert(evt.data);}};
conn.onclose = function(){alert('connection closed');};
}
function readFile(file_data)
{
var video = document.getElementById('area');
video.src = window.URL.createObjectURL(file_data.data);
}
..skip to html element for playing the file..
<video id='area' controls="controls"></video>
I want to be able to receive the file in the browser and play it.
The error I get while trying to send a webm video file to fireox is:
HTTP "Content-Type" of "application/octet-stream" is not supported. Load of media resource blob:794345a5-4b6d-4585-b92b-3acb51612a6c failed.
Is it possible to receive a video file from a websocket and play it?
Am I implementing something wrong?
Video element requires right content-type, ws Blob comes with generic one, and it seems (to me) there is no way to set it serverside or clientside.
Fortunately, Blob has slice(start, end, contentType) method:
var rightBlob = originalBlob.slice(0, originalBlob.size, 'video/webm')
Related
I have to write an application to render PDF documents with Thymeleaf. These documents are stored in a remote server and are accesed through HTTP.
I know it is possible to render PDF documents, when they are stored in the project´s ressource folder. But I don`t want to download them.
Is there any possible way?
I am receiving the file with the following code:
URL url = new URL("http://10.139.1.240:8080/document.pdf");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
if (connection.getResponseCode() == 200) {
try (InputStreamReader streamReader = new InputStreamReader(connection.getInputStream());
BufferedReader br = new BufferedReader(streamReader);
Stream<String> lines = br.lines()) {
Desktop.getDesktop().browse(url.toURI());
} catch (URISyntaxException e) {
throw new RuntimeException(e);
}
}
You could create a method in your controller that allows user to download that file as described in answer to this question, then on the client side, place an iframe pointing to that endpoint .:
<iframe sec="/controller_mapping/method_mapping"/>
You can control it's width and height using style tag.
I'm trying to send a xls file from my java spring server to react client.
Using default Apache POI constructors creates xlsx file, that's not good. In order to override it I have to create the file using FileOutputStream.
FileOutputStream outputStream = new FileOutputStream("file.xls");
But I cannot sent the file over the web. I've tried using the following answer: https://stackoverflow.com/a/54765335/10319765 I quote: "While downloading a file , your code needs to stream a file chunk by chunk - thats what Java streams are for."
return ResponseEntity.ok().contentLength(inputStreamWrapper.getByteCount())
.contentType(MediaType.parseMediaType("application/vnd.ms-excel"))
.cacheControl(CacheControl.noCache())
.header("Content-Disposition", "attachment; filename=" + "file.xls")
.body(new InputStreamResource(inputStreamWrapper.getByteArrayInputStream()));
so my controller is sending InputStreamResource.
How can I construct InputStreamResource using my FileOutputStream?
P.S this is my React client:
axios.get('/issues/export', { responseType: 'arraybuffer' }).then(response => {
if (response && !response.error) {
const blob = new Blob([response.payload.data], {type: 'application/vnd.ms-excel'});
saveAs(blob);
}
});
Source: https://stackoverflow.com/a/46331201/10319765
Edit:
I've managed to do that with a trick, right after I've written to the FileOutputStream I've opened a FileInputStream and returned the value.
FileOutputStream outputStream = new FileOutputStream("file.xls");
workbook.write(outputStream);
workbook.close();
final InputStream fileInputStream = new FileInputStream("file.xls");
return fileInputStream;
but now, the xls file returned as response to the client is corrupted and has weird characters inside:
The excel file should look the following (taken from my java server after sending it):
Issue solved. Eventually what I did in order to solve the corrupted xls file is to work with byte arrays. the controller looks exactly the same but now the return type is ResponseEntity<byte[]>. To convert the InputStream to byte array I've used IOUtils.toByteArray() method.
Client side code has also changed a bit because now the type is no longer responseType: 'arraybuffer' but 'blob'.
axios.get('/issues/export', { responseType: 'blob' }).then(response => {
if (response && !response.error) {
const blob = new Blob([response.payload.data]);
saveAs(blob);
}
});
That's all.
I am downloading a file from the web via HtmlUnit.
This is what my (working) code looks like:
Page dlPage = client.getPage(url);
FileOutputStream fos = new FileOutputStream(destinationFile);
try
{
IOUtils.copy(dlPage.getWebResponse().getContentAsStream(), fos);
}
catch (Exception ex)
{
ex.printStackTrace();
}
finally
{
fos.close();
}
I want to show the download progress. Therefore I need to know the file size. The Content-Length header is sent by the server but the problem is that I can read the headers after the file is downloaded. the getPage() method is blocking until the file is downloaded.
Is there any way to read just the response headers first in HtmlUnit and then the content? Or is there any other way to solve this problem?
Thanks!
You can use getContentLength() method of URLConnection to get the length when the connection is established.
Okay, I figured out a way to get this working: Before the download I send a HEAD request to the server so I can use the response to read the content length:
WebRequest wr = new WebRequest(new URL(url), HttpMethod.HEAD);
Page wrPage = client.getPage(wr);
long contentLength = Integer.valueOf(wrPage.getWebResponse().getResponseHeaderValue("Content-Length"));
System.out.println(contentLength);
I am creating a web application using the Spark Java framework. The front-end is developed using AngularJS.
I want to generate a .docx file on the server (in-memory) and send this to the client for download.
To achieve this I created an angular service with the following function being called after the user clicks on a download button:
functions.generateWord = function () {
$http.post('/api/v1/surveys/genword', data.currentSurvey).success(function (response) {
var element = angular.element('<a/>');
element.attr({
href: 'data:attachment;charset=utf-8;application/vnd.openxmlformats-officedocument.wordprocessingml.document' + response,
target: '_blank',
download: 'test.docx'
})[0].click();
});
};
On the server, this api call gets forwarded to the following method:
public Response exportToWord(Response response) {
try {
File file = new File("src/main/resources/template.docx");
FileInputStream inputStream = new FileInputStream(file);
byte byteStream[] = new byte[(int)file.length()];
inputStream.read(byteStream);
response.raw().setContentType("data:attachment;chatset=utf-8;application/vnd.openxmlformats-officedocument.wordprocessingml.document");
response.raw().setContentLength((int) file.length());
response.raw().getOutputStream().write(byteStream);
response.raw().getOutputStream().flush();
response.raw().getOutputStream().close();
return response;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
I have tried to solve this in MANY different ways and I always end up with a corrupted 'test.docx' that looks like this:
Solved it by using blobs and specifying the response type as 'arraybuffer' in the $http.post api call. The only bad thing with this solution (as far as I know) is that it doesn't play well with IE, but that's a problem for another day.
functions.generateWord = function () {
$http.post('/api/v1/surveys/genword', data.currentSurvey, {responseType: 'arraybuffer'})
.success(function (response) {
var blob = new Blob([response], {type: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'});
var url = (window.URL || window.webkitURL).createObjectURL(blob);
var element = angular.element('<a/>');
element.attr({
href: url,
target: '_blank',
download: 'survey.docx'
})[0].click();
});
};
I think what went wrong was that the byte stream got encoded as plain text when I tried to create a URL with:
href: 'data:attachment;charset=utf-8;application/vnd.openxmlformats-officedocument.wordprocessingml.document' + response
thus corrupting it.
When using blobs instead, I get a "direct" link to the generated byte stream and no encoding is done on it since the response type is set to 'arraybuffer'.
Note that this is just my own reasoning of why things went wrong with the original code. I might be terribly wrong, so feel free to correct me if that's the case.
I'm retrieving a PDF file from a web server java, returning a byte array.
Need save the PDF on the local machine using C #, but the file is saved completely in blank, I think it is because of the byte array format is different.
Here is my code:
StreamReader responseReader = new StreamReader(webStream);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
request.Method = "GET";
request.ContentType = "application/pdf";
WebResponse webResponse = request.GetResponse();
Stream webStream = webResponse.GetResponseStream();
StreamReader responseReader = new StreamReader(webStream);
string response = responseReader.ReadToEnd();
responseReader.Close();
byte[] docByte = Encoding.ASCII.GetBytes(response);
File.WriteAllBytes(#"C:\file.pdf", docByte);
Any suggestions on how to save the PDF file normally?
Thank you for listening
// ...
Stream webStream = webResponse.GetResponseStream();
using (var stream = File.Create(#"C:\file.pdf"))
{
webStream.CopyTo(stream);
}
Why don't you do it simply with WebClient like this?
using System.Net;
using (WebClient webClient = new WebClient())
{
webClient.DownloadFile(URL, #"C:\file.pdf");
}