I want to return the following protobuf serialised binary data to the browser (Chrome) and not as a downloadable file. I don't understand the mechanism that is prompting a download. It is not the mime type as I am using text/plain elsewhere.
Controller:
[HttpGet]
public async Task<ActionResult<string>> GenerateProtoFeed()
{
var feed = _gtfsrService.GenerateFeed();
using (var stream = new MemoryStream())
{
feed.WriteTo(stream);
stream.Position = 0;
using (var reader = new StreamReader(stream))
{
return Content(reader.ReadToEnd(), "text/plain");
}
}
}
What I really want is this (example) to be returned in the browser window:
2.0?????/?
-Mcycmmp9-o4C0qeoGdz*?
????/*0
rE6s0CN800STv61PAKtfHAL6wS0jjmZkSZwq1PAKtf8A08Z?
?
?#StationAlert Elevators at Commercial-Broadway and Brentwood Stations are temporarily out of service today. ^sdken
The browser handles responses from a server differently depending on how the user has configured it, and on the mime type of the response.
It looks like your browser's default behaviour for text/plain is to prompt a save action. If you set the mime type of your response to text/html, the browser should simply display it.
Note that this is of course technically incorrect in this case.
Related
I'm creating a .NET Core 3.1 web api method to download a pdf for a given filename. This method is shared across teams where their client code is generated using NSwag.
I recently changed produces attribute to Produces("Application/pdf") from json, this change is required so other teams can generate valid client code. However since this change, I haven't been able to download any files from this method. Requests to download documents return with a 406 error (in Postman) and the following error is logged to the server event viewer.
No output formatter was found for content types 'application/pdf, application/pdf' to write the response.
Reverting the produced content-type to 'application/json' does allow documents to be downloaded, but as mentioned, this value is required to be pdf.
Any suggestions would be greatly appreciated.
Method:
[HttpGet("{*filePath}")]
[ProducesResponseType(typeof(FileStreamResult), StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
[ProducesResponseType(StatusCodes.Status400BadRequest)]
[ProducesResponseType(StatusCodes.Status401Unauthorized)]
[Produces("Application/pdf")]
public async Task<ActionResult> GetDocument(string fileName) {
RolesRequiredHttpContextExtensions.ValidateAppRole(HttpContext, _RequiredScopes);
var memoryStream = new MemoryStream();
var memoryStream = new MemoryStream();
using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize: 4096, useAsync: true)) {
stream.CopyTo(memoryStream);
}
memoryStream.Seek(offset: 0, SeekOrigin.Begin);
return new FileStreamResult(memoryStream, "Application/pdf");
}
I just came across the same error and after some investigation I found out that the cause of the exception was indeed in the model binding error. You already wrote about it in your answer, but on closer inspection it became obvious that the reason was not related to binding itself, rather to the response body.
Since you specified [Produces("application/pdf")] the framework assumes this content type is the only possible for this action, but when an exception is thrown, you get application/json containing error description instead.
So to make this work for both "happy path" and exceptions, you could specify multiple response types:
[Produces("application/pdf", "application/json")]
public async Task<ActionResult> GetDocument(string fileName)
{
...
}
I'am using
public asnyc Task<IActionResult> BuildPDF()
{
Stream pdfStream = _pdfService.GetData();
byte[] memoryContent = pdfStream.ToArray();
return File(memoryContent, "application/pdf");
}
and it works. Could you please try?
The issue was caused by renaming the method parameter and not updating [HttpGet("{*filePath}")] to [HttpGet("{*fileName}")]
I had the same error, it is very confusing in some cases.
I got this error after adding new parameter of type int[] to my method forgetting [FromQuery] attribute for it.
After adding [FromQuery] attribute error gone.
I'm trying to set up an API that generate PDF from web page (provided as URL). The API is gotenberg from thecodingmachine. I have it on Docker, it works just fine, I can't generate PDF through http request send with curl (for now I'm just trying to make it work, so I use the request provided as example in the documentation)
Now I am trying to make it work with my groovy/grails app. So I'm using the java tools to make the request.
Now here is my problem : the PDF file I get is blank (my app opend directly in my browser). It do has the right content, if I open it with the text editor, it's not empty, and it has almost the same content as the one I make using the curl request (which isn't blank).
I am 99% sure the problem come from the encoding. I tried changing the InputStreamReader encoding parameter, but it doesn't change anything. Here I put "X-MACROMAN" because that the encoding inside the pdf file that isn't blank, but it still doesn't change.
Here is my code :
static def execute(def apiURL)
{
def httpClient = HttpClients.createDefault()
// Request parameters and other properties.
def request = new HttpPost(apiURL)
MultipartEntityBuilder builder = MultipartEntityBuilder.create()
builder.addTextBody("remoteURL", 'https://google.com')
builder.addTextBody("marginTop", '0')
builder.addTextBody("marginBottom", '0')
builder.addTextBody("marginLeft", '0')
builder.addTextBody("marginRight", '0')
HttpEntity multipart = builder.build()
request.setEntity(multipart)
def response = httpClient.execute(request)
BufferedReader rd = new BufferedReader(
new InputStreamReader(response.getEntity().getContent(), "X-MACROMAN"))
StringBuffer result = new StringBuffer()
String line = ""
Boolean a = Boolean.FALSE
while ((line = rd.readLine()) != null) {
if(!a){
a = Boolean.TRUE
}
else {
result.append("\n")
}
result.append(line)
}
return result
I am 99% sure the problem come from the encoding. I tried changing the InputStreamReader encoding parameter, but it doesn't change anything. Here I put "X-MACROMAN" because that the encoding inside the pdf file that isn't blank, but it still doesn't change.
Did I made myself clear ? And does those who understands has any ideas why my PDFs are blank ?
I have a JWS application that caches several different resource types. However, I do not want to cache .svg images. It seems that the framework does not honor the server side cache control HTTP headers that I have set.
I was wondering if there is some other way that I could load .svg images without caching. I am open to putting a solution in my loadSVGDocument() method, but my code is currently built around Apache Batik for loading .svg files. Is there a solution to pass an InputStream with a noCache flag within the Batik library similar to what DocumentBuilderFactory provides below?
URL url = new URL(fileLocation);
URLConnection connection = url.openConnection();
// Prevent JavaWebStart from returning cached copy.
connection.setUseCaches(false);
// Now fetch the content, e.g.
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(connection.getInputStream());
Here is my current loadSVGDocument() method that uses several Apache Batik fields:
public void loadSVGDocument(final String url)
{
System.out.println("THE SVG URL: " + url);
String oldURI = null;
if (svgDocument != null)
{
oldURI = svgDocument.getURL();
}
final ParsedURL newURI = new ParsedURL(oldURI, url);
String theUrl = newURI.toString();
fragmentIdentifier = newURI.getRef();
loader = new DocumentLoader(userAgent);
nextDocumentLoader = new SVGDocumentLoader(theUrl, loader);
nextDocumentLoader.setPriority(Thread.NORM_PRIORITY);
Iterator it = svgDocumentLoaderListeners.iterator();
while (it.hasNext())
{
nextDocumentLoader
.addSVGDocumentLoaderListener((SVGDocumentLoaderListener) it.next());
}
documentLoader = nextDocumentLoader;
nextDocumentLoader = null;
documentLoader.run();
}
For anyone interested, I found that I can call Batik's
DocumentLoader.loadDocument(URL url, InputStream is)
with the setUseCaches flag as false. Not only does this load the image, but it also removes it from the cache accordingly. Though not the best solution in the sense that it would be nice for JWS to honor my HTTP headers, this work-around is good enough.
I have a self-hosted WCF REST/webHttpBinding-endpoint-bound service. I have a few streams of different content types that it serves. The content itself is delivered correctly, but any OutgoingResponse.ContentType setting seems to be ignored and instead delivered as "application/xml" every time.
Browsers seems to get over it for javascript and html (depending on how it's to be consumed), but not for css files which are interpreted more strictly. CSS files are how I realized the problem but it's a problem for all Streams. Chromebug and IE developer tools both show "application/xml" regardless of what I put in the serving code for a content type. I've also tried setting the content type header as a Header in OutgoingResponse but that makes no difference and it probably just a long way of doing what OutgoingResponse.ContentType does already.
[OperationBehavior]
System.IO.Stream IContentChannel.Code_js()
{
WebOperationContext.Current.OutgoingResponse.ContentType = "text/javascript;charset=utf-8";
var ms = new System.IO.MemoryStream();
using (var sw = new System.IO.StreamWriter(ms, Encoding.UTF8, 512, true))
{
sw.Write(Resources.code_js);
sw.Flush();
}
ms.Position = 0;
return ms;
}
This behavior is added:
var whb = new WebHttpBehavior
{
DefaultBodyStyle = System.ServiceModel.Web.WebMessageBodyStyle.WrappedRequest,
DefaultOutgoingRequestFormat = System.ServiceModel.Web.WebMessageFormat.Json,
DefaultOutgoingResponseFormat = System.ServiceModel.Web.WebMessageFormat.Json,
HelpEnabled = false
};
I've tried setting AutomaticFormatSelectionEnabled = true and false just in case because it came up in google searches on this issue, but that has no effect on this.
I'm finding enough articles that show Stream and ContentType working together to confuse the heck out of me as to why this isn't working. I believe that the Stream is only intended to be the body of the response, not the entire envelope.
My .svclog doesn't show anything interesting/relevant that I recognize.
============
I can confirm in Fiddler2 that the headers are being delivered as shown in the browser.
...
Content-Type: application/xml; charset=utf-8
Server: Microsoft-HTTPAPI/2.0
...
Solved!
I had something like the following in a MessageInspector:
HttpResponseMessageProperty responseProperty = new HttpResponseMessageProperty();
responseProperty.Headers.Add("Access-Control-Allow-Origin", "*");
reply.Properties["httpResponse"] = responseProperty;
and this was overwriting the already-present HttpResponseMessageProperty in reply.Properties, including any contentType settings. Instead, I tryget the HttpResponseMessageProperty first and use the existing one if found.
I lucked out seeing that one.
How do I open an existing file on the server when a user clicks an actionlink? The following code works for downloading a file but I want to open a new browser window, or tab, and display the file contents.
public ActionResult Download()
{
return File(#"~\Files\output.txt", "application/text", "blahblahblah.txt");
}
You must add "inline" for a new tab.
byte[] fileBytes = System.IO.File.ReadAllBytes(contentDetailInfo.ContentFilePath);
Response.AppendHeader("Content-Disposition", "inline; filename=" + contentDetailInfo.ContentFileName);
return File(fileBytes, contentDetailInfo.ContentFileMimeType);
The way you're using the File() method is to specify a file name in the third argument, which results in a content-disposition header being sent to the client. This header is what tells a web browser that the response is a file to be saved (and suggests a name to save it). A browser can override this behavior, but that's not controllable from the server.
One thing you can try is to not specify a file name:
return File(#"~\Files\output.txt", "application/text");
The response is still a file, and ultimately it's still up to the browser what to do with it. (Again, not controllable from the server.) Technically there's no such thing as a "file" in HTTP, it's just headers and content in the response. By omitting a suggested file name, the framework in this case may omit the content-disposition header, which is your desired outcome. It's worth testing the result in your browser to see if the header is actually omitted.
Use a target of blank on your link to open it in a new window or tab:
Download File
However, forcing the browser to display the contents is out of your control, as it entirely depends on how the user has configured their browser to deal with files that are application/text.
If you are dealing with text, you can create a view and populate the text on that view, which is then returned to the user as a regular HTML page.
please try this and replace your controller name and action name in html action link
public ActionResult ShowFileInNewTab()
{
using (var client = new WebClient()) //this is to open new webclient with specifice file
{
var buffer = client.DownloadData("~\Files\output.txt");
return File(buffer, "application/text");
}
}
OR
public ActionResult ShowFileInNewTab()
{
var buffer = "~\Files\output.txt"; //bytes form this
return File(buffer, "application/text");
}
this is action link which show in new blank tab
<%=Html.ActionLink("Open File in New Tab", "ShowFileInNewTab","ControllerName", new { target = "_blank" })%>
I can´t vote your answered as is useful, follow dow. Thanks very much !
public FileResult Downloads(string file)
{
string diretorio = Server.MapPath("~/Docs");
var ext = ".pdf";
file = file + extensao;
var arquivo = Path.Combine(diretorio, file);
var contentType = "application/pdf";
using (var client = new WebClient())
{
var buffer = client.DownloadData(arquivo);
return File(buffer, contentType);
}
}