Is it true that if use createBlobURL(), file data is not loaded into memory? So is it alright to use it for images and video?
After looking at the WebKit source I would say the function only creates an URL in the following form:
blob:<encoded original url>/<uuid>
There doesn't seem to appear any loading of the URL's source.
The file contents are not loaded into JS memory, but the browser does create a handle to the file. So, calling createObjectURL() doesn't come for free. Chrome has a nice chrome://blob-internals/ page to see all the Blob URLs created.
Just remember to call revokeObjectURL() when you're done.
Related
I have a very simple site and all the CSS for it is written in one file, so whenever any page is requested the CSS file is loaded. So I was wondering if there is someway, that I can tell the browser to use the same file it loaded a second ago instead of requesting it again.
I assume you have the css loaded externally then? I don't believe there is a way to natively do that unfortunately. But, if you're proficient in javascript, I suppose you could save all of the css file as a string using the localStorage property in the browser. Then request the data you want loaded specifically per site.
Local storage persists after the browser is closed, so it would only need to be loaded once!
I'm currently "learning" d3js by myself and I found a lot of examples here. It seems that for all the visualizations we need two separated files. One is a script (an html file) and the other one is a json file which contains our data set.
I'm curious if there is a way to put the json file into html file so we can have only one file. I think I saw an example like this previously on the internet but I lost it.
The only reason I want to do it like this is that if data set is separated from html file, I cannot use Chrome to view my result (I think Chrome is blocking the script from reading local data set). I can use Firefox to open up my result but the animation doesn't perform smoothly.
Maybe some of my understanding is not really right. But if there is any suggestions please let me know. Thanks in advance.
If you're just using one HTML file, you probably have a <script> tag on your page where all the code is located. You can define your data as a Javascript array.
It can be nice to use multiple files to organize code, data, and view elements (the HTML). This page gives some help on setting your browser to let you do that. For Chrome, close all open windows. Then run Chrome from the 'Run' prompt with this flag: chrome --allow-file-access-from-files
I have created a SWF file using Flash that loads an FLV file on my local development machine. When publishing the SWF file and generating the appropriate HTML, I can successfully load the video by opening the generated HTML page that Flash creates. However, when placing the generated HTML code in my View, the Flash is loading, but the video is not playing. I think it's a reference error to the location of the FLV file, but I've tried every combination I can think of. I placed the SWF and FLV in the corresponding View folder where I want the video to load, but to no avail. Does anyone have a working example that I can look at, or any suggestions? Thanks.
I think it's a reference error to the location of the FLV file, but I've tried every combination I can think of.
Yes, I think so as well. Have you tried using Url helpers to reference static resources on your site, like
#Url.Content("~/Content/Videos/MySupervideo.flv")
The actual solution to this for me was this...
In your Flash file, the Component Inspector should point to the location on the web server where the FLV file is located...
Publish the SWF, copy the appropriate HTML to the View you would like the video to play in...
And just as Darin has pointed out, use the Helpers to write the path to the SWF file on your web server where it is located. The only difference is this (which I discovered using Google's 'Inspect Element' feature and then clicking on the 'Network' item, then clicking the path loaded on the left for the 'SWF'... on the right it stated 404 Status Not Found... why?
#Url.Content("~/Content/video/name-of-swf.swf") actually produced
src='http://localhost/content/video/name-of-swf.swf.swf'
This obviously incorrect... so here is the correct way to use the Helpers...
#Url.Content("~/Content/video/name-of-swf")
Hope this helps someone... I am giving Darin credit because he pushed me in the right direction...
Does HTML 5 allow to invoke save file dialog with file created in JavaScript?
Yes, but you don't really need HTML5 for it, what you can use is a Data URI. There are several limitations, like IE8 only allows files up to 32Kb, and you'll need to get the user to click on a link. See my answer to a similar question for an example.
In the future you may be able to use the File Writer API, but I'm not aware of any browser support for that yet.
I've tested data-uri approach. Currently it works only in Firefox.
Seems that for now it is better to stay with flash: https://github.com/dcneiner/Downloadify
I am trying to create a "smart" web browser to load local images. Basically it works as a GUI for an application. I am using QTWebKit to power the browser, the problem is that the images of a given page can be found in different places, some are local files, others are in different resource files.
For example:
an HTML node to load image x.jpg can look like <img src="x.jpg"> and for image y.gif on the same page it can be <img src="y.gif">, now x.jpg is a local file that can be either in the root directory or in some other place. y.gif on the other hand can be in a resource file.
I want the web browser first to set the paths to all possible sources and once the page has been loaded or preferably while the page is loading searches for the images and loads them from their original path.
I considered the option of reading the HTML data first, parse it and search for the resources one by one, then edit the html to include the full path of the image but that would take a long time than what I want and it isn't practical.
Can any one put me on the right direction or does any one have any ideas on how such a design can be implemented.
EDIT: I have manage to delegate the requests by overriding the QNetwrokAccessManager and QNetwrokReply and been able to get the path to the image. The only problem is loading the image into view. I am currently using QHttp to handle the incoming requests but so far I haven't been able to load the image.
been trying to use QHttp's Get() function and passing the path to the jpg image as (file:///path/to/image) and also tried using the local path but nothing is working.
Take a look at How to tell QWebPage not to load specific type of resources?
You need the same approach but instead of dropping request by constructing QNetworkRequest with empty QUrl you need to pass url to the file on the disk.