Add CSS outside WebContext

Hi,

I’m using thymeleaf to generate PDF in background processes (batch) using Spring Boot 2…

To add some style to my PDF’s I would like to add some CSS using this.

<link rel="stylesheet" href="static/css/CDM.css" th:href="@{/static/css/CDM.css}"/>

Then I got the following exception :

org.thymeleaf.exceptions.TemplateProcessingException: Link base "/static/css/CDM.css" cannot be context relative (/...) unless the context used for executing the engine implements the org.thymeleaf.context.IWebContext interface 

I’ve seen this issue on github but I don’t get how I could get a WebContext in a batch process?

How could I load my CSS files so that they are applied in my PDF?

I’ve seen this issue. But I don’t get how to make it work outside a WebContext…

[danielfernandez]

Very late for a response, but the thing is, a context-relative URL can only be resolved when the template is being executed as a part of a web application running as such in a web server… because it’s web servers who create web contexts, that serve as a root for such URLs.

So this means your template needs to be executed by means of the normal Spring Boot web mechanisms (i.e. as a Spring view) in order to get to execute that kind of links. As opposed to, for instance, having your own TemplateEngine instance and executing it on your own.

However, most PDF-producing mechanism I know actually do this: start a web server, make it render a page, perform an HTTP request, and then render the result into the PDF… and this rendering phase is needed precisely because you are applying styles, so maybe you should be setting a separate web server for your PDF exporter?

Given this is a quite old ticket and you mentioned you already had a workaround I will be closing it now. But plese don’t hesitate opening if there is anything else you needed to add.

[ultraq]

Hi @schtrym, sorry for not getting back to you sooner, but is this still an issue for you? If so, the problem you’re running up against is that you can’t use @{...} expressions outside of a web context because that particular expression looks up some information on the running web server to fill out things like the scheme, protocol, domain, port, etc… These, obviously, don’t exist in a batch process.

However, do you know where your CSS files will live relative to the output template that you’re creating? If so, you can drop the th:href="@{...}" and instead fill in the standard href attribute to contain the relative path to the CSS file, eg: href="../static/css/CSM.css". Or if your CSS file lives on a web server that you know the address of, you can fill in the href with that address, eg: href="http://localhost:8080/static/css/CDM.css"