Ruby on rails webpacker can't find images unde

问题:

I have a problem with including images in my views using Ruby on Rails Webpacker. When i try to insert image in my view using html img tag and asset_pack_path i got an error. My images is located in app/javascript/images/logo.png. According to webpacker docs i should append /media/ to file but it does not help. I try diffrent path but it's still not working. I think webpacker doesn't compile my image.

Webpacker::Manifest::MissingEntryError in Home#index
Showing app/views/layouts/application.html.haml where line #14 raised:

Webpacker can't find media/logo.png in public/packs/manifest.json. Possible causes:
1. You want to set webpacker.yml value of compile to true for your environment
   unless you are using the `webpack -w` or the webpack-dev-server.
2. webpack has not yet re-run to reflect updates.
3. You have misconfigured Webpacker's config/webpacker.yml file.
4. Your webpack configuration is not creating a manifest.
Your manifest contains:
{
  "application.js": "/packs/js/application-321d1c3bcc175b7f61a6.js",
  "application.js.map": "/packs/js/application-321d1c3bcc175b7f61a6.js.map",
  "entrypoints": {
    "application": {
      "js": [
        "/packs/js/application-321d1c3bcc175b7f61a6.js"
      ],
      "js.map": [
        "/packs/js/application-321d1c3bcc175b7f61a6.js.map"
      ]
    },
    "hello_react": {
      "js": [
        "/packs/js/hello_react-c48c89eaf873362b846b.js"
      ],
      "js.map": [
        "/packs/js/hello_react-c48c89eaf873362b846b.js.map"
      ]
    }
  },
  "hello_react.js": "/packs/js/hello_react-c48c89eaf873362b846b.js",
  "hello_react.js.map": "/packs/js/hello_react-c48c89eaf873362b846b.js.map"
}

In my view application.html.haml

!!! 5
%html
  %head
   = javascript_pack_tag 'application', 'data-turbolinks-track': 'reload'
    = stylesheet_pack_tag    'application'
  %body
    %nav.navbar.navbar-expand-lg.navbar-light.bg-primary
      %a.navbar-brand(href="/")
        %img(src="#{asset_pack_path 'media/logo.png'}")

app/javascript/packs/application.js

require.context('../images', true)

import 'bootstrap'
import './src/application.scss' 

Procfile.dev

web: bundle exec rails s
webpacker: ./bin/webpack-dev-server

webpacker.yml

# Note: You must restart bin/webpack-dev-server for changes to take effect

default: &default
  source_path: app/javascript
  source_entry_path: packs
  public_root_path: public
  public_output_path: packs
  cache_path: tmp/cache/webpacker
  check_yarn_integrity: false
  webpack_compile_output: false

  # Additional paths webpack should lookup modules
  # ['app/assets', 'engine/foo/app/assets']
  resolved_paths: []

  # Reload manifest.json on all requests so we reload latest compiled packs
  cache_manifest: false

  # Extract and emit a css file
  extract_css: false

  static_assets_extensions:
    - .jpg
    - .jpeg
    - .png
    - .gif
    - .tiff
    - .ico
    - .svg
    - .eot
    - .otf
    - .ttf
    - .woff
    - .woff2

  extensions:
    - .jsx
    - .mjs
    - .js
    - .sass
    - .scss
    - .css
    - .module.sass
    - .module.scss
    - .module.css
    - .png
    - .svg
    - .gif
    - .jpeg
    - .jpg

development:
  <<: *default
  compile: true

  # Verifies that versions and hashed value of the package contents in the project's package.json
  check_yarn_integrity: true

  # Reference: https://webpack.js.org/configuration/dev-server/
  dev_server:
    https: false
    host: localhost
    port: 3035
    public: localhost:3035
    hmr: false
    # Inline should be set to true if using HMR
    inline: true
    overlay: true
    compress: true
    disable_host_check: true
    use_local_ip: false
    quiet: false
    headers:
      'Access-Control-Allow-Origin': '*'
    watch_options:
      ignored: '**/node_modules/**'


test:
  <<: *default
  compile: true

  # Compile test packs to a separate directory
  public_output_path: packs-test

production:
  <<: *default

  # Production depends on precompilation of packs prior to booting for performance.
  compile: false

  # Extract and emit a css file
  extract_css: true

  # Cache manifest.json for performance
  cache_manifest: true

回答1:

My images are located in /app/assets/images.

Firstly add app/assets to resolved_paths: ['app/assets'] in webpacker.yml

And then you can use the image in your JS like so:

<img src='~images/logo.png' />

in CSS:

<style lang='sass'>
#app
  background: url('~images/logo.png')
</style>

回答2:

It looks like the path is not in the manifest file.

In Rails 6 there are two commented lines in application.js. Regardless of what rails version you're running just make sure you add them in:

const images = require.context('../images', true)
const imagePath = (name) => images(name, true)

Alternatively, you can force the images to be added to the manifest by moving your folder inside packs, eg. packs/images. The path would change though to media/images/your-file.png.

For seeing if the path exists or not, I found it easier to just lookup it up from ruby directly:

Webpacker.manifest.send(:data).keys.grep /logo/

回答3:

I had an issue with getting images to show up in Rails 6. I did this:

Add image to

assets/custom_folder/img_filename.file_extension

Uncomment two lines in javascript/packs/application.js

const images = require.context('../images', true)
const imagePath = (name) => images(name, true)

Then add your image to your erb file using this: (I had an index.html.erb view file)

<%= image_tag("custom_folder/file_name.file_extension")%>

This worked for me, hope it helped.

Check out this link