cant use with swagger

[yeli19950109]

cant use with swagger for nestjs

[styfle]

Hello @yeli19950109

Can you create an example that fails with ncc build?

[dominique-mueller]

I'm experiencing the same issue, the path to the Swagger UI assets is no longer correct after building the app with ncc.

After some playing around, however, I've seem to found a workaround: Serving the static folder manually, after the Swagger setup. Here's a code snippet, I'm using /swagger as the public URL:

// ...

SwaggerModule.setup('/swagger', app, document);

app.useStaticAssets(join(__dirname, '/static'), {
  prefix: '/swagger',
});

// ...

Plus, I had to install fastify-swagger although I'm just using express in NestJS ... just wtf?

This all works for now, but surely is not a very pretty solution ...

[dominique-mueller]

The real issue is probably how swagger-ui itself gets built and served, and not necessarily how ncc tries to bundle it up. Related issue: scottie1984/swagger-ui-express#114.

[mohammadzainabbas]

Any updates on this one ??

p.s: @dominique-mueller I have tried your proposed solution and it seems that I might be missing something out. Could you be kind enough to help me out with this issue ??

[dominique-mueller]

@mohammadzainabbas Sure, I took the time to prepare a repository here: https://github.com/dominique-mueller/ncc-nestjs-swagger-experiment. It's a working example, so you can clone it and play around with it. I also wrote a quick explanation in the README about what has to be done to get Swagger working in an existing ncc-NestJS project. Hope it helps!

[eMarek]

I have issues with swagger-ui-express as well after using ncc. @dominique-mueller, thank you for your example. I am wondering if it would be possible to achieve similar fix with express only? I am not using nestjs in my project.

[tmtron]

So my understanding of the issue is that swagger-ui works like this:
When a browser requests the swagger documentation URL (e.g. https://example.com/swagger/):

• the swagger-ui module builds a dynamic html file and returns it to the client
  • this contains relative links to some files: e.g.swagger-ui-bundle.js, swagger-ui.css etc.
  • so these files must be accessible from the client browser

"normal" build (i.e. without ncc)

installed packages

• in the root of our project we have all dependencies in node_modules available
• according to the NestJs Swagger Docs we install the npm packages:
  • @nestjs/swagger
  • swagger-ui-express

dependencies

• We use the NestJs SwaggerModule in our code, which will require('swagger-ui-express'), which in turn has a dependency on:
• swagger-ui-dist which is a small package that contains the assets
  that swagger-ui needs at runtime: e.g.swagger-ui-bundle.js, swagger-ui.css etc.

Runtime

When the server is running and the browser visits the swagger URL (e.g. https://example.com/swagger/):

• express will handle the request
• the GET request for this path has been registered by the NestJs SwaggerModule
  • and this returns the dynamic HTML page created by swagger-ui-express
  • this HTML contains relative links:
    so the browser will send new requests to get these files e.g. https://example.com/swagger/swagger-ui-bundle.js
    • these requests are also handled by express and the routes have been registered by
      swagger-ui-express
      , which just forwards the GET requests to the swagger-ui-dist package
    • this works, because the package is required and NodeJs will resolve it according to its algorithm which in this case will find the swagger-ui-dist package in the top-level node_modules folder

"ncc" build:

installed packages

None: in this case we don't have access to node_modules/swagger-ui-dist
i.e. the reason to use ncc is that we don't need the large node_modules folder.

Runtime

So when we don't do anything special the swagger-html page will not work, because the requests for the
relative links in the dynamic HTML cannot be resolved (express will return a HTTP 404 - Not Found error)

Fix

To fix this we must somehow provide these files. This requires 2 steps

1. copy the relevant files to a folder which will be accessible (by node) at runtime, when we start the ncc output
2. tell express to send those files to the client-browser when the correct URL is requested

copy files

This depends on your build tools: e.g. we use angular-cli, thus we can simply use assets to copy the relevant files, e.g.

"assets": [
   {
   "glob": "**/*.{js,css,html,png}",
   "input": "./node_modules/swagger-ui-dist/",
   "output": "./dist/assets/swagger-ui-dist/"
   },
   ....
]

Where dist is the ncc output dir (i.e. where the index.js or main.js file will be created)

serve files

When we use NestJs we can use this:

app.useStaticAssets(path.join(__dirname, 'assets/swagger-ui-dist/'), {
  prefix: '/swagger'
});

where app is our NestExpressApplication.
So basically this just configures express to return the files in the assets/swagger-ui-dist/ folder when the URL starts with /swagger: e.g. https://example.com/swagger/swagger-ui-bundle.js

Why installing "fastify-swagger" seems to work

This refers to the explanation in the ncc-nestjs-swagger-setup test project

I guess the reason is this:

When ncc analyses our code, it finds require('fastify-swagger') in the SwaggerModule.
When the package is installed (i.e. exists in node_modules), ncc will process it.
When the webpack-asset-relocator-loader
(used by ncc) will notice that the file prepare-swagger-ui.js needs the files in the static folder:

And thus it will copy these files to the static folder in our dist dir.
Now we could serve these files and the swagger URL may work.

I think this may not work reliably, because there is no guarantee that the swagger-ui-dist version which is copied from the fastify-swagger package is compatible to the version used by swagger-ui.

So I think it's better to

• not include fastify-swagger
• and instead copy the files from /node_modules/swagger-ui-dist
  • which exists it is listed as a dependency of swagger-ui-express

[Onihani]

I was experiencing the same issue.
Fortunately I got it to work without ncc.
My solution is a bit hacky.
Check out my solution on stack overflow: https://stackoverflow.com/a/74708365/13701992

[ramazansancar]

This is how I solved the problem.
Deploying Platform: Vercel

[kangfenmao]

I wrote a patch to solve this problem. use https://unpkg.com/swagger-ui-dist@5.6.2/ as publicUrl

diff --git a/node_modules/@nestjs/swagger/dist/swagger-ui/constants.js b/node_modules/@nestjs/swagger/dist/swagger-ui/constants.js
index 6f47648..8776139 100644
--- a/node_modules/@nestjs/swagger/dist/swagger-ui/constants.js
+++ b/node_modules/@nestjs/swagger/dist/swagger-ui/constants.js
@@ -1,8 +1,8 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.jsTemplateString = exports.htmlTemplateString = exports.favIconHtml = void 0;
-exports.favIconHtml = '<link rel="icon" type="image/png" href="<% baseUrl %>favicon-32x32.png" sizes="32x32" />' +
-    '<link rel="icon" type="image/png" href="<% baseUrl %>favicon-16x16.png" sizes="16x16" />';
+exports.favIconHtml = '<link rel="icon" type="image/png" href="<% publicUrl %>favicon-32x32.png" sizes="32x32" />' +
+    '<link rel="icon" type="image/png" href="<% publicUrl %>favicon-16x16.png" sizes="16x16" />';
 exports.htmlTemplateString = `
 <!-- HTML for static distribution bundle build -->
 <!DOCTYPE html>
@@ -10,7 +10,7 @@ exports.htmlTemplateString = `
 <head>
   <meta charset="UTF-8">
   <title><% title %></title>
-  <link rel="stylesheet" type="text/css" href="<% baseUrl %>swagger-ui.css" >
+  <link rel="stylesheet" type="text/css" href="<% publicUrl %>swagger-ui.css" >
   <% favIconString %>
   <style>
     html
@@ -71,8 +71,8 @@ exports.htmlTemplateString = `
 
 <div id="swagger-ui"></div>
 
-<script src="<% baseUrl %>swagger-ui-bundle.js"> </script>
-<script src="<% baseUrl %>swagger-ui-standalone-preset.js"> </script>
+<script src="<% publicUrl %>swagger-ui-bundle.js"> </script>
+<script src="<% publicUrl %>swagger-ui-standalone-preset.js"> </script>
 <script src="<% baseUrl %>swagger-ui-init.js"> </script>
 <% customJs %>
 <% customJsStr %>
diff --git a/node_modules/@nestjs/swagger/dist/swagger-ui/swagger-ui.js b/node_modules/@nestjs/swagger/dist/swagger-ui/swagger-ui.js
index c067725..d60f616 100644
--- a/node_modules/@nestjs/swagger/dist/swagger-ui/swagger-ui.js
+++ b/node_modules/@nestjs/swagger/dist/swagger-ui/swagger-ui.js
@@ -55,6 +55,7 @@ function buildSwaggerHTML(baseUrl, swaggerDoc, customOptions = {}) {
         .replace('<% explorerCss %>', explorerCss)
         .replace('<% favIconString %>', favIconString)
         .replace(/<% baseUrl %>/g, baseUrl)
+        .replace(/<% publicUrl %>/g, 'https://unpkg.com/swagger-ui-dist@5.6.2/')
         .replace('<% customJs %>', toTags(customJs, toExternalScriptTag))
         .replace('<% customJsStr %>', toTags(customJsStr, toInlineScriptTag))
         .replace('<% customCssUrl %>', toTags(customCssUrl, toExternalStylesheetTag))

Patch file

@nestjs+swagger+7.1.10.patch

[gaffarmalik]

My swagger UI now shows with the correct CSS/JS after relocating it. But it still shows up as with the example "Petstore". Is there some kind of document (json) that's missing?