I am working on a project where we have a database and a separate file system both stored on the same server and are accessed through service stack requests and responses.
The database contains the relevant metadata for a given file in the file system and as such we would like to be able to retrieve and store these files and documents simultaneously to prevent orphaned data.
Is is possible to return both a stream of data (file) and a response DTO in the same response? Similar to how JsonServiceClient.PostFileWithRequest allows for both a file and request DTO to be passed to the server. If it is possibly how would it be handled on both the server and client sides?
In my research so far most applications appear to just return either a response document or a stream and mostly through the use of HttpResult.
Thanks in advance!
There's no support for MIME Multipart/mixed responses which is primarily for Email and rarely supported and used for HTTP. The easiest way to send additional metadata with your File download response is to use HTTP Headers, e.g:
return new HttpResult(fileInfo) {
Headers = {
{"X-key", "value"}
}
};
Another option would be to embed the contents of the file inside a DTO:
class FileResponseWithMetadata
{
public byte[] Data { get; set; }
public string Key { get; set; }
}
For returning multiple files you'd need to zip the files using a library like DotNetZip and return that instead.
Related
I am trying to select a local json file and load it in my blazor client component.
<input type="file" onchange="LoadFile" accept="application/json;.json" class="btn btn-primary" />
protected async Task LoadFile(UIChangeEventArgs args)
{
string data = args.Value as string;
}
P,S I do not understand , do i need to keep track both the name of the file and the content when retrieving it ?
I guess you're trying to read the contents of a JSON file on the client (Blazor), right? Why not on the server !?
Anyhow, args.Value can only furnish you with the name of the file. In order to read the contents of the file, you can use the FileReader API (See here: https://developer.mozilla.org/en-US/docs/Web/API/FileReader). That means that you should use JSIntrop to communicate with the FileReader API. But before you start, I'd suggest you try to find out if this API have been implemented by the community (something like the localStorage, etc.). You may also need to deserialize the read contents into something meaningful such as a C# object.
Hope this helps...
There is a tool that can help, but it currently doesn't support the 3.0 preview. https://github.com/jburman/W8lessLabs.Blazor.LocalFiles
(no affiliation with the developer)
The input control will give you the location of the file as a full path along with the name of the file. Then you still have to retrieve the file and download it to the server.
Late response but with 3.1 there is an additional AspNetCore.Components module you can download via NuGet to get access to HttpClient extensions. These make it simple:
// fetch mock data for now
var results = await _http.GetJsonAsync<WellDetail[]>("sample-data/well.json");
You could inject the location of the file from your input control in place of the "sample-data/well.json" string.
Something like:
using Microsoft.AspNetCore.Components;
private async Task<List<MyData>> LoadFile(string filePath)
{
HttpClient _http;
// fetch data
// convert file data to MyData object
var results = await _http.GetJsonAsync<MyData[]>(filePath);
return results.ToList();
}
For web browsers (such as Chrome, IE, or Firefox), when you select a file using a "Choose File" button, where does the file's data get stored?
The file name shows in the browser, but does the data of the file get stored anywhere or is just a link to the file put somewhere, such as in the browser or a temporary file?
To clarify: I want to know where the file's data get's stored BEFORE submitting. JUST after the file is selected from the client's PC an not anything else is done.
After you select a file. I believe the client (browser) just stores a reference to the file location on the user's computer. It takes a combination of js and html to post the file to the server. Via a Multi/form-data Post.
In this case, on the server, you may have to store the file to a temp location of your choosing, until you're able to process it (i.e. transform and/or store to a Datastore).
In newer browsers you can use the FormData object and xhr to post to the server which is a lot cleaner.
This FormData object is used to construct the key/value pairs which form the data payload for the xhr request.
// Create a new FormData object.
var formData = new FormData();
In this case, once the file bytes are posted to the server, you can do whatever you want with that data. Typically I'll store it as a blob in the DB.
This approach will allow you to keep it all in memory. People make the mistake of trying to store on the server file system. In some multipart form post, you might have to do it this way, however.
Here's some of my web api upload code when using XHR.
I've also called this API route using an iframe (ugh!) in order to support IE8 and older. POS browsers!
/// <summary>
/// Upload the facility logo.
/// </summary>
/// <returns></returns>
[HttpPost]
[Route("logo")]
public HttpResponseMessage Logo()
{
int newImageId = -1;
var uploadedFiles = HttpContext.Current.Request.Files;
if (uploadedFiles.Count > 0)
{
var file = uploadedFiles[0];
if (!file.IsImage())
{
// "The uploaded file must be a .jpg, .jpeg, or .png"
return
Request.CreateResponse(HttpStatusCode.UnsupportedMediaType,
"unsupported");
}
var facilityRepository = new FacilityRepository();
var logoBytes =
StreamCopier.StreamToByteArray(file.InputStream, file.ContentLength);
newImageId = facilityRepository.InsertLogoImage(logoBytes);
}
return Request.CreateResponse(HttpStatusCode.OK,
newImageId);
}
Good day, I'm working on a Servlet that must return a PDF file and the message log for the processing done with that file.
So far I'm passing a boolean which I evaluate and return either the log or the file, depending on the user selection, as follows:
//If user Checked the Download PDF
if (isDownload) {
byte[] oContent = lel;
response.setContentType("application/pdf");
response.addHeader("Content-disposition", "attachment;filename=test.pdf");
out = response.getOutputStream();
out.write(oContent);
} //If user Unchecked Download PDF and only wants to see logs
else {
System.out.println("idCompany: "+company);
System.out.println("code: "+code);
System.out.println("date: "+dateValid);
System.out.println("account: "+acct);
System.out.println("documentType: "+type);
String result = readFile("/home/gianksp/Desktop/Documentos/Logs/log.txt");
System.setOut(System.out);
// Get the printwriter object from response to write the required json object to the output stream
PrintWriter outl = response.getWriter();
// Assuming your json object is **jsonObject**, perform the following, it will return your json object
outl.print(result);
outl.flush();
}
Is there an efficient way to return both items at the same time?
Thank you very much
HTTP protocol doesn't allow you to send more than one HTTP response per one HTTP request. With this restriction in mind you can think of the following alternatives:
Let client fire two HTTP requests, for example by specifyingonclick event handler, or, if you returned HTML page in the first response, you could fire another request on window.load or page.ready;
Provide your for an opportunity of choosing what he'd like to download and act in a servlet accordingly: if he chose PDF - return PDF; if he chose text - return text and if he chose both - pack them in an archive and return it.
Note that the first variant is both clumsy and not user friendly and as far as I'm concerned should be avoided at all costs. A page where user controls what he gets is a much better alternative.
You could wrap them in a DTO object or place them in the session to reference from a JSP.
I am a new bie on GWT, I wrote an application on abc.com, I have another application i.e. xyz.com, xyz.com?id=1 provides me a data in json format, I was thinking to find a way that how to get that json file in abc.com via RPC call, because I have seen tutorials in which RPC calls are used to get data from its server. any help will be appreciated.
EDIT
I am trying to implement this in this StockWatcher tutorial
I changed my code slightly change to this
private static final String JSON_URL = "http://localhost/stockPrices.php?q=";
AND
private void refreshWatchList() {
if (stocks.size() == 0) {
return;
}
String url = JSON_URL;
// Append watch list stock symbols to query URL.
Iterator iter = stocks.iterator();
while (iter.hasNext()) {
url += iter.next();
if (iter.hasNext()) {
url += "+";
}
}
url = URL.encode(url);
MyJSONUtility.makeJSONRequest(url, new JSONHandler() {
#Override
public void handleJSON(JavaScriptObject obj) {
if (obj == null) {
displayError("Couldn't retrieve JSON");
return;
}
updateTable(asArrayOfStockData(obj));
}
});
}
before when I was requesting my url via RequestBuilder it was giving me an exception Couldn't retrieve JSON but now JSON is fetched and status code is 200 as I saw that in firebug but it is not updating on table. Kindly help me regarding this.
First, you need to understand the Same Origin Policy which explains how browsers implement a security model where JavaScript code running on a web page may not interact with any resource not originating from the same web site.
While GWT's HTTP client and RPC call can only fetch data from the same site where your application was loaded, you can get data from another server if it returns json in the right format. You must be interacting with a JSON service that can invoke user defined callback functions with the JSON data as argument.
Second, see How to Fetch JSON DATA
Most of the solutions I've come across for Sharepoint doc library uploads use the HTTP "PUT" method, but I'm having trouble finding a way to do this in Silverlight because it has restrictions on the HTTP Methods. I visited this http://msdn.microsoft.com/en-us/library/dd920295(VS.95).aspx to see how to allow PUT in my code, but I can't find how that helps you use an HTTP "PUT".
I am using client web-services, so that limits some of the Sharepoint functions available.
That leaves me with these questions:
Can I do an http PUT in Silverlight?
If I can't or there is another better way to upload a file, what is it?
Thanks
Figured it out!! works like a charm
public void UploadFile(String fileName, byte[] file)
{
// format the destination URL
string[] destinationUrls = {"http://qa.sp.dca/sites/silverlight/Answers/"+fileName};
// fill out the metadata
// remark: don't set the Name field, because this is the name of the document
SharepointCopy.FieldInformation titleInformation = new SharepointCopy.FieldInformation
{DisplayName =fileName,
InternalName =fileName,
Type = SharepointCopy.FieldType.Text,
Value =fileName};
// to specify the content type
SharepointCopy.FieldInformation ctInformation = new SharepointCopy.FieldInformation
{DisplayName ="XML Answer Doc",
InternalName ="ContentType",
Type = SharepointCopy.
FieldType.Text,
Value ="xml"};
SharepointCopy.FieldInformation[] metadata = { titleInformation };
// initialize the web service
SharepointCopy.CopySoapClient copyws = new SharepointCopy.CopySoapClient();
// execute the CopyIntoItems method
copyws.CopyIntoItemsCompleted += copyws_CopyIntoItemsCompleted;
copyws.CopyIntoItemsAsync("http://null", destinationUrls, metadata, file);
}
Many Thanks to Karine Bosch for the solution here: http://social.msdn.microsoft.com/Forums/en/sharepointdevelopment/thread/f135aaa2-3345-483f-ade4-e4fd597d50d4
What type of SharePoint deployment and what version of silverlight? If say it is an intranet deployment you could use UNC paths to access your document library in sharepoint and the savefiledialog/openfiledialog available in Silverlight 3.
http://progproblems.blogspot.com/2009/11/saveread-file-from-silverlight-30-in.html
or
http://www.kirupa.com/blend_silverlight/saving_file_locally_pg1.htm
Silverlight has restrictions on what it can do with local files, though I've read that silverlight 4 has some changes.
http://www.wintellect.com/CS/blogs/jprosise/archive/2009/12/16/silverlight-4-s-new-local-file-system-support.aspx