Next.js 公共图像未在生产版本中显示

Question

I have a Next.js app I am deploying to Heroku. When I dev locally I see the images, but when I push to Heroku and check the site, the images have a 404. I have a public folder where I have the images (.png) right in the folder, and the code I reference the image like this

<Image
    src="/wb_blue_white.png"
    alt="WB Concept"
    width="70"
    height="70"
    className={navStyles.logo}
/>

Both locally and in prod the if I look at the image source they are the same src="/_next/image?url=%2Fwb_blue_white.png&w=256&q=75" but I get a 404 in prod. What could be causing the image to show up localhost but not in Heroku prod build?

package.json

"scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start -p $PORT"
},

file structure

components
pages
public

Answer 1

I was having this same problem. For me the issue was not the components at all. I was hosting my site on Netlify, and I didn't realize that by default Netlify builds the devDependencies. So node packages for development/testing were accidentally getting compiled for production.

I changed the NODE_ENV (in Netlify) to production and reorganized the packages between dependencies and devDependencies ... and the error went away.

I think that the components triggered this issue because the initial request(s) cause them to be generated/optimized server-side. So even though the build succeeded. The remote image request caused dev packages to run in the wrong context.

I hope this someday helps someone else.

Answer 2

Check out next custom server doc and its example repo .

Here in this express-looking code that's used to configure the server, app.render() seems to be setting routes for nextjs page , ie /a to pages/a . I'm not sure if that's even needed for each path or done for demo purpose. Try fiddling around.

Anyway, if it's anything like basic express server, which I suspect, use() method on express instance will add a "middleware", which 1. takes the request and 2. passes it to next middleware, or sends the response to client.

With server.use(express.static(path.join(__dirname, 'public'))); , where server is the express instance in this case and fortunately(convention actually) in the example repo as well, you can add the middleware that handles static files serve.

I've forgotten the exact way of configuring express, but i'm guessing either:

• right after the express() instantiation, or
• right before the listen()

should do the trick. Just put server.use(express.static(path.join(__dirname, 'public'))) in there.

Answer 3

Create a directory for images in the root folder and import, relatively, from there. Does the trick.

Answer 4

There are several articles on this, but basically Sharp is required and should be installed. The wording in the NextJS docs makes it sound optional, but with the default loader, Sharp is required .