I am using QWebPage to download some pages, including the js rendered content. But I found that sometimes, there is some js missing. The content which should be replaced by js rendering result remains empty.
I check the document for QWebPage, I guess I got the answer, “Finally, the loadFinished() signal is emitted when the page contents are loaded completely, independent of script execution or page rendering.”
But how can I wait until all script rendering finish.
Related
I want to convert an HTML page written with Vue.js to a vector-based PDF client-side. I understand there are solutions in the backend, however, in my case I specifically want client-side. I have very complex Vue components and styling which I would like to print to pdf. I tried multiple approaches and I could not find a solution.
Here is what I tried: -
The easiest way I found is window.print().
The issue with this approach, is that there is no other way to invoke the download functionality directly without going through the pop-dialog. Another issue I found window.onafterprint and window.onbeforeprint event listeners don't work on firefox but work in chrome. In firefox, both events fire at the same time. regardless, I do not like the default dialog, I would rather build my own.
I retrieved the HTML and CSS from the DOM using this.$el.innerHTML, and window.getComputedStyle(element) and saved them to a variable, then converted to blob and downloaded it with javascript.
this solution worked, however only in DEV build, since I bundle my app with Vite, the computed styles don't render on the DOM as I expected when in Production build; which I believe is due to the way Vite bundles CSS for optimization. Therefore the result will only be HTML with no styling.
I used the popular vue-html2pdf library and it is straightforward.
the issue with this approach is the fact it simply renders HTML and CSS to an image the saves as a pdf, therefore the output will be an image-based-pdf. which is not my preferred kind of pdf.
I cannot find any library that takes in HTML and CSS and covert to a Vector-based pdf on the client-side.
Title says it all. I'm developing a Vue app that is going to be used as a display for my instance of Home Assistant. I tell it what JS file to load and what tag to use and HA puts it inside an iframe. The font I'm using is an otf file.
It seems like my component can only use the font when it gets included in the page's section. Since I'm not generating the page or the iframe, I can't add anything to the head. The only thing I can figure out to do is use JS to add the font face to the head after the page is loaded. I've seen a react component do this. Is there a build option or something?
But it is my understanding the whole point of web components is to be able to include a single JS file then use the component. Does this not include fonts or other resources?
I am trying to use one of the Material Design Lite templates inside my Vue.js application.
What happens is, when I am routed(using this.$router.push('/templateX') to the next page, the component is not fully rendered(I can see only the header).
What is really interesting, when I take a look at the source section inside the browser console, I can see that the template is loaded but not fully rendered.
Once I reload the page, then the whole template is rendered and everything is shown as expected.
I think the problem is in the component life cycle but I am not sure what shall I do exactly. Any thoughts?
I'm trying to understand the usage and limitations of server side rendering with vuejs when using aspnet core.
I used this starter kit for aspnet core and vuejs to setup a simple vue site, which is running based on the code here: https://github.com/selaromdotnet/aspnet-vue-ssr-test/tree/master
I then modified the project to update the aspnet-prerendering and added vue-server-renderer, compiling a hodgepodge of sources to cobble together this update: https://github.com/selaromdotnet/aspnet-vue-ssr-test/tree/ssr
If I run this project, the site appears to load fine, and if I turn off the javascript in the browser, I can see that it does appear that the server-side rendering executed and populated the html result:
however, because JavaScript is disabled, the content isn't moved into the dom as it looks like it is trying to...
My understanding of server-side rendering is that it would populate the html entirely and serve a completed page to the user, so that even if JS was disabled, they'd at least be able to see the page (specifically for SEO purposes). Am I incorrect?
Now I believe modern search engines will execute simple scripts like this to get the content, but I still don't want a blank page rendered if js is disabled...
Is this a limitation of server-side rendering, or perhaps specifically ssr with vue and/or aspnet core?
or am I just missing a step somewhere?
Edit: more information
I looked at the source code for what I believe is the method that prerenders the section here: https://github.com/aspnet/JavaScriptServices/blob/dev/src/Microsoft.AspNetCore.SpaServices/Prerendering/PrerenderTagHelper.cs
The line
output.Content.SetHtmlContent(result.Html);
has a null value for result.Html. However, when I manually edit this value to put a test value, it also doesn't render to the output html, and the app div tag is still empty...
If I'm doing something wrong to populate the result.Html value with the expected output, that's one thing, and I would appreciate some help in doing that, especially since the output html appears to be found, since it's in the script that immediately follows...
However, even if I were to populate it, it appears it's being skipped, as evidenced by me manually changing the value. is this a bug in the code or am I doing somethigng wrong, or perhaps both?
As you correctly noticed, for your project, result.Html inside the tag helper is null. So that line cannot be the location where the output is being generated. Since the HTML output from your prerendering script also does not include a script tag, it is clear that something has to generate that. The only other line that could possible do this is the following from the PrerenderTagHelper:
output.PostElement.SetHtmlContent($"<script>{globalsScript}</script>");
That would fit the observed output, so we should figure out where the globalsScript comes from.
If you look at the PrerenderTagHelper implementation, you can see that it will call Prerenderer.RenderToString which returns a RenderToStringResult. This result object is deserialized from JSON after calling your Node script.
So there are two properties of interest here: Html, and Globals. The former is responsible for containing the HTML output that finally gets rendered inside the tag helper. The latter is a JSON object containing additional global variables that should be set for the client side. These are what will be rendered inside that script tag.
If you look at the rendered HTML from your project, you can see that there are two globals: window.html and window.__INITIAL_STATE__. So these two are set somewhere in your code, although html shouldn’t be a global.
The culprit is the renderOnServer.js file:
vue_renderer.renderToString(context, (err, _html) => {
if (err) { reject(err.message) }
resolve({
globals: {
html: _html,
__INITIAL_STATE__: context.state
}
})
})
As you can see, this will resolve the result containing just a globals object with both html and __INITIAL_STATE__ properties. That’s what gets rendered inside of the script tag.
But what you want to do instead is have html not as part of globals but on the layer above, so that it gets deserialized into the RenderToStringResult.Html property:
resolve({
html: _html,
globals: {
__INITIAL_STATE__: context.state
}
})
If you do it like that, your project will properly perform server-side rendering, without requiring JavaScript for the initial view.
Windows Phone 8 app, WebBrowser control. I load a chunk of HTML via NavigateToString (after setting IsScriptEnabled=true). Some time later (long after it's loaded), I'm invoking some JavaScript on the page with InvokeScript.
When I invoke a JavaScript function that's defined inline inside a <script> element, it works as expected. When I invoke one that's defined in an external JS file, it doesn't, and an exception from HRESULT 0x80020006 ("name not found") is thrown.
The external script file is loaded from my app package. In the HTML string, there's a <base> element which contains a file:// URL to the package's folder (retrieved via Package::Current->InstalledLocation), and the <script> element contains just the file name. There are also styles and images in that folder - they load fine.
The HTML has no DOCTYPE and no xmlns - I know those things can sometimes throw JavaScript off.
The external script file is valid - it came straight from Android where it worked on the respective WebView control. The function I'm trying to invoke is empty anyway, to be on the safe side, JavaScript syntax-wise.
This could in theory be some kind of a cross-domain scripting issue. Technically, the script comes from a file:// URL while the page itself comes from no URL at all. Some piece of system code that makes sure no fishy script is called could've gotten in the way.
Found one workaround: load the external script file into a string on startup, once the HTML is loaded (LoadCompleted fires), feed it to the document using JavaScript eval.
Here is example of how to inject some script dynamically
Browser.InvokeScript("eval", new string[] { FileUtils.ReadFileContent("app/www/js/console.js") });
Where ReadFileContent could be defined as following
https://github.com/sgrebnov/IeMobileDebugger/blob/master/Libraries/Support/FileUtils.cs
Full example
https://github.com/sgrebnov/IeMobileDebugger/blob/master/Libraries/IE.Debug.Core/WebPageDebugger.cs
PS. instead of reading script from file you can pass hardcoded string, etc
Are you sure that your script is being loaded? One thing you can do is tuck an alert in there to make sure it is being loaded. My suspicion is that it isn't being loaded.
Any time I have run into this before that has been the case although admittedly I haven't loaded a JS file from Isolated Storage before.