How can I tell grunt-usemin to ignore Django's static template tags?

Question

I'm building a Django app that serves a single page Angular app.

Django serve's Angular's index.html which has the following usemin script block:

<!-- build:js scripts/scripts.js -->
<script src="{% static "scripts/app.js" %}"></script>
<script src="{% static "scripts/controllers/main.js" %}"></script>
<script src="{% static "scripts/controllers/stats.js" %}"></script>
<script src="{% static "scripts/directives/highchart.js" %}"></script>
<!-- endbuild -->

Usemin tries to find "{% static "scripts/app.js" %}" on the filesystem and of course fails because what it should really be trying to find is "scripts/app.js".

Has anyone seen a workaround for this?

Answer 1

Alright, I think I have a workaround. This is assuming you want the built file to also point to the static url for the built assets.

This will require you to define a STATIC_URL on your view context (instead of using src="{% static 'foo/bar.js' %}" you'll use src="{{STATIC_URL}}foo/bar.js"). I couldn't get {% static %} to work without hacking the grunt-usemin source.

So using your example, this:

<!-- build:js {{STATIC_URL}}scripts/scripts.js -->
<script src="{{STATIC_URL}}scripts/app.js"></script>
<script src="{{STATIC_URL}}scripts/controllers/main.js"></script>
<script src="{{STATIC_URL}}scripts/controllers/stats.js"></script>
<script src="{{STATIC_URL}}scripts/directives/highchart.js"></script>
<!-- endbuild -->

Compiles down to:

<script src="{{STATIC_URL}}scripts/scripts.js"></script>

In order to achieve this, I had to add the following grunt configurations (in Gruntfile.js):

// custom createConfig script for replacing Django {{STATIC_URL}} references
// when building config for concat and cssmin
var path = require('path');
function createDjangoStaticConcatConfig(context, block) {
  var cfg = {files: []};
  var staticPattern = /\{\{\s*STATIC_URL\s*\}\}/;

  block.dest = block.dest.replace(staticPattern, '');
  var outfile = path.join(context.outDir, block.dest);

  // Depending whether or not we're the last of the step we're not going to output the same thing
  var files = {
    dest: outfile,
    src: []
  };
  context.inFiles.forEach(function(f) {
    files.src.push(path.join(context.inDir, f.replace(staticPattern, '')));
  });
  cfg.files.push(files);
  context.outFiles = [block.dest];
  return cfg;
}


grunt.initConfig({
    /*...*/

    // add a preprocessor to modify the concat config to parse out {{STATIC_URL}} using the above method
    useminPrepare: {
      html: 'app/index.html',
      options: {
        dest: 'dist',
        flow: {
          steps: {
            js: [
              {
                name: 'concat',
                createConfig: createDjangoStaticConcatConfig
              },
              'uglifyjs'
            ],
            // also apply it to css files
            css: [
              {
                name: 'cssmin',
                createConfig: createDjangoStaticConcatConfig
              }
            ]
          },
          // this property is necessary
          post: {}
        }
      }
    },

    // add a pattern to parse out the actual filename and remove the {{STATIC_URL}} bit
    usemin: {
      html: ['dist/{,*/}*.html'],
      css: ['dist/styles/{,*/}*.css'],
      options: {
        assetsDirs: ['dist'],
        patterns: {
          html: [[/\{\{\s*STATIC_URL\s*\}\}([^'"]*)["']/mg, 'django static']]
        }
      }
    },


    // if you are using bower, also include the jsPattern to automatically 
    // insert {{STATIC_URL}} when inserting js files
    'bower-install': {
      app: {
        html: 'app/index.html',
        jsPattern: '<script type="text/javascript" src="{{STATIC_URL}}{{filePath}}"></script>'
      }
    }
});

Answer 2

(I keept finding this question when googling for a solution, so I just share the solution i found here so that others like me can find it.)

I just discovered a grunt plugin called grunt-bridge that can wrap static files in a html template with the static tag. The documentation is not great but I figured how to get it to work for my project.

If you have scripts like this:

<!-- build:js({.tmp,app}) /scripts/scripts.js -->
    <script src="scripts/app.js"></script>
    <script src="scripts/util/util.js"></script>
    ...

And the final output it to output something like this:

<script src="{% static 'adjangoappname/scripts/94223d51.scripts.js' %}"></script>

Install gruntbridge with npm install grunt-bridge --save-dev and add a config like this in the grunt.initConfig of the Gruntfile.js:

bridge: {
  distBaseHtml: {
      options: {
          pattern: '{% static \'adjangoappname{path}\' %}',
          html: '<%= yeoman.minifiedDir %>/index.html', dest: '<%= yeoman.templateDir %>/index.html'
      }
  },
  distIndexHtml: {
      options: {
          pattern: '{% static \'adjangoappname{path}\' %}',
          html: '<%= yeoman.minifiedDir %>/index.html', dest: '<%= yeoman.templateDir %>/index.html'
      }
  },
  // ... etc for each html file you want to modify
},

Where <%= yeoman.minifiedDir %> is the output directory of the final minified html files, and <%= yeoman.minifiedDir %> is the destination template directory. Replace adjangoappname with the name of your django app or whatever directory prefix you want to have.

Then add grunt-bridge last in the registerTask list like this:

grunt.registerTask('build', [
    //...
    'htmlmin',
    'bridge'
]);

(I think it's possible to make the config more compact, but this is the first method I discovered that worked)