I am using streams to download the excel file. Please find the code below
$response = new \Zend\Http\Response\Stream();
$response->setStream(fopen($myfile, 'r'));
$response->setStatusCode(200);
$headers = new \Zend\Http\Headers();
$headers->addHeaderLine("Content-Type: application/vnd.ms-excel; charset=UTF-8")
->addHeaderLine('Content-Disposition', 'attachment; filename=my.xls')
->addHeaderLine( "Content-Transfer-Encoding: binary" )
->addHeaderLine('Content-Length', filesize($myfile));
$response->setHeaders($headers);
The file generated is proper but when the same file I am enforcing the user to download there are two empty lines coming in the downloaded excel file. I did some researching and thought may it's http version and header lines but I think it's not because if I try otherwise I get those two empty line in start of excel report.
Please note there are no empty space in the start of the content.
Any idea ?? why it's so?
Mind the streamed response does in fact not really provide a stream context to the client. It just buffers the stream internally and sends out the response in one go.
That being said, I have created a controller plugin to send attachments from a file path or directly with the binary data addressed to a variable. It's in my common Soflomo\Common library. I haven't had the issues you described and I use some more headers than you do.
Tell me if that piece of code works for you. One of the differences is you use the size of the original file as the size of the response. I am not sure, as this might cause an indifference with the cached streamed response. Try to just grab the contents and do a strlen() on this content.
Related
Is it possible to download a file nested in a zip file, without downloading the entire zip archive?
For example from a url that could look like:
https://www.any.com/zipfile.zip?dir1\dir2\ZippedFileName.txt
Depending on if you are asking whether there is a simple way of implementing this on the server-side or a way of using standard protocols so you can do it from the client-side, there are different answers:
Doing it with the server's intentional support
Optimally, you implement a handler on the server that accepts a query string to any file download similar to your suggestion (I would however include a variable name, example: ?download_partial=dir1/dir2/file
). Then the server can just extract the file from the ZIP archive and serve just that (maybe via a compressed stream if the file is large).
If this is the path you are going and you update the question with the technology used on the server, someone may be able to answer with suggested code.
But on with the slightly more fun way...
Doing it opportunistically if the server cooperates a little
There are two things that conspire to make this a bit feasible, but only worth it if the ZIP file is massive in comparison to the file you want from it.
ZIP files have a directory that says where in the archive each file is. This directory is present at the end of the archive.
HTTP servers optionally allow download of only a range of a response.
So, if we issue a HEAD request for the URL of the ZIP file: HEAD /path/file.zip we may get back a header Accept-Ranges: bytes and a header Content-Length that tells us the length of the ZIP file. If we have those then we can issue a GET request with the header (for example) Range: bytes=1000000-1024000 which would give us part of the file.
The directory of files is towards the end of the archive, so if we request a reasonable block from the end of the file then we will likely get the central directory included. We then look up the file we want, and know where it is located in the large ZIP file.
We can then request just that range from the server, and decompress the result...
I have a node app (specifically sails app) that is serving pdf file. My code for serving file looks like this.
request.get(pdfUrl).pipe(res)
And when I view the url for pdf, it renders the pdf fine. But sometimes, it just renders the binary data of pdf on browser like given below.
%PDF-1.4 1 0 obj << /Title (��) /Creator (��wkhtmltopdf
I am not able to figure out why is it failing to serve the pdf correctly just randomly. Is it chrome thing? or Am I missing something?
Leaving this here in the hope that it helps somebody - I have had similar issues multiple times and its either of two things:
You're using an HTTP connection to an HTTPS delivery (this is typical with websockets, where you must specify :443 in addition to the wss.
request's encoding parameter is serving plaintext instead of objects. This is done by setting encoding to null as follows: request({url: myUrl, encoding: null}).
Content types in headers - steering clear of this since it's obvious/others have covered this substantially enough already :)
I am pretty sure you're facing this due to (2). Have a look at https://github.com/request/request
encoding - Encoding to be used on setEncoding of response data. If
null, the body is returned as a Buffer. Anything else (including the
default value of undefined) will be passed as the encoding parameter
to toString() (meaning this is effectively utf8 by default). (Note: if
you expect binary data, you should set encoding: null.)
Since, the aforementioned suggestions didn't work for you, would like to see forensics from the following:
Are files that fail over a particular size? Is this a buffer issue at some level?
Does the presence of a certain character in the file cause this because it breaks some of your script?
Are the meta-data sections and file-endings the same across a failed and a successful file? How any media file is signed up-top, and how it's truncated down-bottom, can greatly impact how it is interpreted
You may need to include the content type header application/pdf in the node response to tell the recipient that what they're receiving is a PDF. Some browsers are smart enough to determine the content type from the data stream, but you can't assume that's always the case.
When Chrome downloads the PDF as text I would check the very end of the file. The PDF file contains the obligatory xref table at the end. So every valid PDF file should end with the following sequence: %EOF. If not then the request was interrupted or something gone wrong.
You also need HTTP header:
Content-Disposition:inline; filename=sample.pdf;
And
Content-Length: 200
Did you try to save what ever binary stuff you get on disk and open it manually by PDF reader? It could be corrupt.
I would suggest trying both of these:
Content-Type: application/pdf
Content-Disposition: attachment; filename="somefilename.pdf"
(or controlling Mime Type in other ways: https://www.npmjs.com/package/mime-types)
So I have a use case where the client uploads a small TSV file, the file is opened and parsed on the server, and results are written to a new file on the server.
Since the TSV file will be tiny (under 1 MB), I am wondering if it is even necessary to upload the file to the server (writing it to disk) before parsing it. Instead, could the file contents be captured when the user clicks "upload file"? I could then store the file contents in an array, each item representing a line in the file.
Thoughts?
You don't need to stream the file to disk, but be aware that you should set clear and concise limits so that a person could not, say, upload a 5GB file and make your service crash from memory exhaustion. You just need to be aware that you're limited to your available amount of memory(likely less) when you process something completely in memory. It's also possible to stream parse it, so that you don't need to save it to disk before parsing it. In your case it sounds easiest to just upload it into memory, and make certain that you put a limit(maybe like 5mb limit) on the upload file size.
Are you asking whether this option is feasible or whether it's a good idea?
Regarding feasibility, it is entirely possible using the FileReader API to parse the content and then a simple Meteor.call onto whatever method is appending to the file on disk. The code would like like follows:
function onSubmit(event, template) {
var file = template.$('.your-file-input-elemt').files[0];
var filereader = new FileReader();
filereader.onload = function(fileevent) {
Meteor.call('processTSV', filereader.readAsText(file));
};
}
If you're talking about whether it's a good idea, then it comes down to browser support. Are you okay with users without the FileReader API not getting support from your application? If so it's considerably easier to deal with than handling uploads with something like CollectionFS.
I have a problem that closely relates to this problem Microsoft Excel Error: "There was a problem sending the command to the program." whereby opening Excel gives There was an error sending a command to the program error.
However, rather than the file existing and being opened or shortcutted-to, I am using MVC3 with an action that generates a bunch of data, generates an excel file (using NPOI), writes it to a MemoryStream and then chucks that to the browser using the built-in return File(etc) ActionResult, with something akin (but shortened here to aid readability) to this:
return File(myMemoryStream, "application/vnd.ms-excel", "filename.xls");
The first time you click the link which fires this action and returns this File - it comes up with the error. if you press ok and try it again it works, and will continue to work... forever
Now I know this is potentially something to do with disabling DDE/plug-ins or something in Excel - but since I'm generating an excel workbook and dumping it to a memory stream rather than opening something that exists permanently on the file system, I'm not sure what options I have to remove the issue.
Any suggestions on how to get around it? Perhaps I have the wrong mime-type?
The Content-Type application/vnd.ms-excel is sending the command to the Browser to open the file in the Browser. Which can be the cause of issue. Try setting the content type to application/x-msexcel.
In your example the browser will try to open an Excel spreadsheet in the browser (if the user has Excel installed).
return File(myMemoryStream, "application/vnd.ms-excel", "filename.xls")
Please make the following change
return File(myMemoryStream, "application/x-ms-excel", "filename.xls")
I hope my Q was clear ... I am curious about the typical way to code for someone clicking File|Open, and selecting a file that is inappropriate for the program--like someone using a word processing program and trying to open a binary file.
In my case, my files have multiple streams streamed together. I'm unsure how to have the code validate whether an improper file was selected before the app throws a stream read exception. (Or is the way to handle the situation to just write code to catch a stream read exception?)
Thanks, as always.
I think it's quite usual that you have code that just tries to open the file, and if it fails, an error is shown to the user. Most file formats has some kind of header with a "magic number", so that the reader can tell if it's not the right file very quickly after reading the first few bytes of the file.
Magic number at the start of the file generally helps -- if you have control of the file format.
Otherwise, yeah -- catch the exception and put up a dialog.