Need to add image to existing xls file in rails 2? - javascript

I am reading .xls file through spreadsheet gem and i can successfully update the content, but unable to add image to xls file , please provide any solutions to my problem.

From what I can see, there's nothing out there that can do what you want short of actually automating Excel, which you can do from Ruby using WIN32OLE http://ruby-doc.org/stdlib-2.2.2/libdoc/win32ole/rdoc/WIN32OLE.html.
In order to do that, however, you'll have to be running Rails on Windows with Excel installed. You'll also probably only be able to process one document at a time per server (either physical or virtualized).
If your app is not hosted on Windows (I presume it isn't), you could write a separate application to do the processing and call out to it as a service from your main application. You'd still have to host that on Windows somewhere though.

Related

Is there any way to open file in its default application using JavaScript?

I want to open a file in its Windows default application.
Actually, the scenario is as below:
A file is saved in Database and it is shown as a preview in CKEditor
When I double click on that file, it should open in its default application. The file can be a Word or Excel or PDF file
Then the user will edit the file in that default application
And when the user saves that file or closes the document, it should be updated on the server also it should refresh the file preview in CKEditor
I just want to know if there is any way to open the file in its default application.
Things I have tried:
I tried to use the ActiveX object to open the file, but it is not supported in Chrome and Firefox. And anyway, many forums are saying that it is the end of ActiveX era.
Tried to find if there is any CKEditor plugin, but did not find any.
Thank you in advance for your answer.
Short answer: no. Can you imagine the security nightmare if JavaScript was allowed to execute arbitrary binary files on a user's machine?
Your solution is going to be to find a JavaScript library that allows for handling those files, similar to how PDF.js was made for PDFs in-browser.

Excel file download using MS Edge

My app creates an excel file, server side, from a database extraction.
A post request sends parameters to the server that the server then uses to query the database.
The server uses these parameters to extract data convert the data to an excel file (xlsx), then saves the file with a certain file-name as per the parameters sent to the server.
The server responds to the post request by sending the file-name to the browser.
The browser then creates a link using the filename and other predefined parameters to download the file by the following instructions:
var link = 'http://host-name/path-to-file/excel-file.xlxs'; // the link that is created by the js in the browser
window.location = link; // the file is downloaded
This works in chrome, firefox, opera and safari, in these browsers, the file downloads no problem.
However; when running in Microsoft-edge, the file is not downloaded and this appears in the page.
Someone was facing similar issue in some versions of IE and had to set Cache-Control header to make the download working properly:
response.Cache.SetCacheability(HttpCacheability.Private);
Source
The issue here is that this method of downloading files is not actually downloading the file. I was using javascript to instruct the browser to open the excel file, window.location = link;. Which tells the browser, go to a that link, and open whatever you find at that address. Which is normally an HTML file or something else transpiled into HTML. This can in some cases be also be a .pdf or the sort of file that modern web-browsers are able to interpret and run.
Now, the reason this was mostly working is; browsers like chrome and firefox are smart enough to know that they cannot interpret and display excel files, so instead, they download them. Pretty smart right. However; microsoft-edge is not so clever as its more proven compatriots. It tries to interpret and run the file, which of course it cannot. What this then leads to; is a grand display of nonsense; as you can see from screen-grab in my question above.
My problem here was actually a deeper rooted issue of technology mismatch. I had since migrated to using a more modern stack, replacing my plain node.js server with express. Moving the front-end out of a cross-origin tomcat java-container application-server model (which was causing most of my headaches on a daily bases since I was coding javascript) to a same-origin environment using webpack along with express.
And as you might know, using webpack brings a whole new dimension to the front-end that was not available before when we were using the 'old approach' to web-dev.
Most of the improvements in using webpack came from its ability to bring 'node.js' to the front end.
It has made my life as a dev 150% easier and the type of problem as described in my question above is now a thing of the past. javascript for the win! The moral for me here is that sometimes that aren't any quick fixes, and you just have to do things properly.

Build URL to data file download with link to folder

I have a web application that triggers actions at the server side which result in the generation of data files.
The so generated data files are stored within a folder at drive different from the one where the Web application is.
What I tried so far is to create a shortcut (Windows Server) next to the Index.html, where the shortcut points to the folder at the second drive.
This solution does not appear to work:
If I copy the data file to the same folder where the Index.html file is and enter navigate to the URL httm://127.0.0.1:324324/Data_File.xlsx I get the file downloaded.
If I enter httm://127.0.0.1:324324/MyShortcut/Data_File.xlsx (where MyShortcut points to a folder in drive D) the attempt fails.
How can I achieve this?
The need to access files in the different drive is essential.
You need to configure your server to serve that folder under different location. The only reason you are able to see your app and access that folder is cause server is set up to serve it ATM, not because you are making the right calls from the front or cause the front is asking nicely.
Don't know what Windows server version you are using and IIS version that goes on it, or are you even using IIS (you most probably do) but depending on what you use you need to do something in a lines of this:
IIS7 config
What you probably wanna do is create virtual folder in IIS. Try looking into it, then if you fail ask a question with proper tags according where are you stuck.
I don't see how this is connected to front-end at all so front end tags wont get you far.
EDIT:
Oh, in that case get a second file server running for that folder? This should be the fastest way, use what you can from this list: list

I want to convert an huge excel workbook (with multiple tabs) and few columns and rows hidden on WEB Page

When I tried saving the excel sheet in HTML and displaying I've got few problems:
The numbers in each cell are distorted
Hidden rows and columns are displayed (I want them to keep hidden)
Top rows of my Excel sheet are freezed, I want them to keep freezed.
The Sheet is updated daily and I want the changes to be reflected in Web as well.
Could you suggest a way other than saving excel sheet in HTML? Any other way I could start this project?
P.S: I hold the knowledge of HTML, CSS, JavaScript.
Do I need to learn any additional skill set to get pull this project?
If you are running IIS or can otherwise run .NET code on your server, you can use the Open XML SDK. There are plenty of examples of using the SDK. Apparently, it even works with Mono if you're using Apache.
If not, if you've got some machine that can get to the Excel file and copy files to your web server and from which you can run a scheduled task, you can schedule a task on that machine that using the Open XML SDK to translate the Excel file to HTML, then upload that HTML to the server.
It doesn't have to be a complete page; it can just be the parts of the HTML you need. You can then have some JavaScript on the page that fires off an AJAX request to get the HTML file. This is true regardless of whether your serving content dynamically generated by code running under IIS or a static file generated by code elsewhere and pushed to the server.
You might have something like:
<!-- page where the spreadsheet should go -->
<div id="put-excel-worksheet-here"></div>
Then:
$.ajax({
url: "/path/to/converted-data-partial-html.html"
, success: function(excelHtml) {
$("#put-excel-worksheet-here").append($(excelHtml));
}
});
And your ASP.NET page response or scheduled task would convert your Excel file to something like <table><thead><tr><th id='column-one-th'>....
Either way, I'd recommend you work with a copy of the file rather than the original, since I've found Office can get a little finicky with files being open in two places at once.
As for freezing the top rows, here's a fiddle with an example.
Good luck!
edit: As an alternative to putting millions of cells worth of HTML onto a single page, it might make sense load the Excel data into a relational database like MySQL or Microsoft SQL Server and do some custom web development to pull the data out of that with pagination and filters and other nice reporting features.
If the data in the Excel file is coming OUT of another system, you might be able to set up a system-to-system integration. If not through an integration, though, the Open XML SDK is how I'd do it. You don't have millions of rows to put up per your comments above, so this suggestion doesn't make sense.
edit: Oh, and I recommend your scheduled task run during a time when people aren't likely going to be using the system. If, for example, your users are all in a few adjacent time zones, have the task run at 3:00 AM in the Eastern-most time zone.

How can I use Javascript to perform background updates of a Phonegap application?

I am using PhoneGap to develop an application for Android and iOS, and recently in a discussion about this technology, someone told me a seemingly brilliant idea that I can do background updates of my application without having to submit a new application to the app store.
The problem is that, being that I am still fairly new to the HTML5/CSS and Javascript world, I cannot figure out how to download files to my www directory for permanent storage. I can dynamically load JS code or HTML pages at runtime, but I want to create some javascript module that will find that a certain .css, .html, or .js file is out of date, download the new version of that file from some http or file server to the www directory, and then have that new file permanently saved so that it is available the next time the app is opened.
I feel like this should be simple, but I can't figure out how to do it. Thanks in advance.
In order to permanently save files to the devices you will need to make use of the PhoneGap File APIs. Periodic tasks can be achieved with a simple Javascript timer.

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