Nuxt•3w ago

how to extend nuxt security headers after build using enviroment vars?

Hi all nuxt noob here, (i am php backend developer normally) I have a nuxt project that is deployed to a static webapp on azure along with a cdn also deployed automatically, i dont know the cdn url before build and i want to add it to allow images from cdn.

security: {
    headers: {
      contentSecurityPolicy: {
        'img-src': [
          "'self'",
          'data:',
          'https://*.googleapis.com',
          'https://*.gstatic.com',
          'https://*.google.com',
          process.env.NUXT_PUBLIC_IMAGE_CDN
        ],
        'script-src': [
          "'self'",
          'https:',
          "'unsafe-inline'",
          "'unsafe-eval'",
        ],
      }
    }
  }

security: {
    headers: {
      contentSecurityPolicy: {
        'img-src': [
          "'self'",
          'data:',
          'https://*.googleapis.com',
          'https://*.gstatic.com',
          'https://*.google.com',
          process.env.NUXT_PUBLIC_IMAGE_CDN
        ],
        'script-src': [
          "'self'",
          'https:',
          "'unsafe-inline'",
          "'unsafe-eval'",
        ],
      }
    }
  }

thats what i currently have in the nuxt.config.js which doesnt seem to work I found that I can add hooks like ready

  hooks: {
    ready(nuxt) {
      nuxt.options.security.headers.contentSecurityPolicy['img-src'].push(nuxt.options.runtimeConfig.public.IMAGE_CDN)
    }
  }

  hooks: {
    ready(nuxt) {
      nuxt.options.security.headers.contentSecurityPolicy['img-src'].push(nuxt.options.runtimeConfig.public.IMAGE_CDN)
    }
  }

I tried that from a suggestion from chatgpt but it doesnt work and i cant seem to find how to access the security headers to update them i would appritiate the help

14 Replies

kapa.ai•3w ago

Hi @ACuriousProgrammer. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- To extend Nuxt security headers after build using environment variables, you'll need to understand a few key concepts about how Nuxt handles runtime configuration and environment variables. Here's how you can approach this: 1. First, it's important to note that .env files are not used in production. As mentioned in the Nuxt documentation (https://nuxt.com/docs/guide/directory-structure/env#production), after your server is built, you're responsible for setting environment variables when you run the server. 2. For production, you should set the environment variables using the tools provided by your hosting environment (in your case, Azure). The variable should be prefixed with NUXT_ to be applied to the runtime config. 3. In your nuxt.config.ts, you should define the runtime config:

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      IMAGE_CDN: '' // can be overridden by NUXT_PUBLIC_IMAGE_CDN environment variable
    }
  },
  // ... other config
})

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      IMAGE_CDN: '' // can be overridden by NUXT_PUBLIC_IMAGE_CDN environment variable
    }
  },
  // ... other config
})

4. To access this runtime config in your application, you can use the useRuntimeConfig composable. However, for security headers, you'll need a server-side solution. 5. One approach is to use a server middleware to set the headers. Create a file in your server/middleware directory, for example security-headers.ts:

export default defineEventHandler((event) => {
  const config = useRuntimeConfig()
  
  setResponseHeaders(event, {
    'Content-Security-Policy': `img-src 'self' data: <https://*.googleapis.com> <https://*.gstatic.com> <https://*.google.com> ${config.public.IMAGE_CDN}; script-src 'self' https: 'unsafe-inline' 'unsafe-eval';`
  })
})

export default defineEventHandler((event) => {
  const config = useRuntimeConfig()
  
  setResponseHeaders(event, {
    'Content-Security-Policy': `img-src 'self' data: <https://*.googleapis.com> <https://*.gstatic.com> <https://*.google.com> ${config.public.IMAGE_CDN}; script-src 'self' https: 'unsafe-inline' 'unsafe-eval';`
  })
})

This middleware will run for every request and set the Content-Security-Policy header using the IMAGE_CDN value from your runtime config. Remember to set the NUXT_PUBLIC_IMAGE_CDN environment variable in your Azure environment with the CDN URL. Note that this approach sets the headers for every request, which might not be as performant as setting them at the web server level. If possible, consider configuring these headers in your Azure CDN or Web App settings for better performance. Nuxt Runtime Config (https://nuxt.com/docs/guide/going-further/runtime-config#environment-variables) H3 setHeaders utility (https://h3.unjs.io/utils/response#setheadersevent-headers) Remember, the hooks approach you mentioned doesn't work because hooks are executed at build time, not at runtime. The server middleware approach allows you to set headers dynamically at runtime. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•3w ago

<@1314567457892995113> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

ACuriousProgrammerOP•3w ago

@kapa.ai thanks for the help so far, if middleware can reduce performance what else you do you recommend, i already do points 1, 2, 3

kapa.ai•3w ago

Let me check the knowledge base for you again. One moment! :books: ---------------------- I'm glad I could help earlier. You're right to be concerned about performance, and it's great that you've already implemented points 1, 2, and 3. Let's explore some alternative approaches that might be more performant for extending Nuxt security headers after build using environment variables: 1. Use a reverse proxy: Instead of setting headers in Nuxt, you could use a reverse proxy like Nginx or Apache to set the security headers. This approach is typically more performant as it handles headers at the web server level. You can configure the proxy to read environment variables and set the appropriate headers. 2. Azure CDN configuration: If you're using Azure CDN, you can configure custom rules to add or modify headers. This approach is highly performant as it sets headers at the CDN level. You can use Azure CDN's rules engine to dynamically set the Content-Security-Policy header based on environment variables. 3. Azure Web App configuration: For Azure Web Apps, you can configure custom headers in the web.config file. This method is also performant as it sets headers at the web server level. You can use environment variables in the web.config file to dynamically set the headers. 4. Nitro runtime configuration: Nuxt 3 uses Nitro as its server engine. Nitro provides a way to set headers at runtime using environment variables. You can create a nitro.config.ts file in your project root and configure headers there. This approach is more performant than middleware as it's integrated into the Nitro server setup. Here's an example of how you might use this approach:

   import { defineNitroConfig } from 'nitropack'
export default defineNitroConfig({
     routeRules: {
       '/**': {
         headers: {
           'Content-Security-Policy': () => `img-src 'self' data: <https://*.googleapis.com> <https://*.gstatic.com> <https://*.google.com> ${process.env.NUXT_PUBLIC_IMAGE_CDN}; script-src 'self' https: 'unsafe-inline' 'unsafe-eval';`
         }
       }
     }
   })

   import { defineNitroConfig } from 'nitropack'
export default defineNitroConfig({
     routeRules: {
       '/**': {
         headers: {
           'Content-Security-Policy': () => `img-src 'self' data: <https://*.googleapis.com> <https://*.gstatic.com> <https://*.google.com> ${process.env.NUXT_PUBLIC_IMAGE_CDN}; script-src 'self' https: 'unsafe-inline' 'unsafe-eval';`
         }
       }
     }
   })

This configuration will apply the headers to all routes and use the environment variable at runtime. These approaches should provide better performance compared to using middleware. The best choice depends on your specific deployment setup and requirements. Nitro Configuration (https://nitro.unjs.io/config) Azure CDN Rules Engine (https://docs.microsoft.com/en-us/azure/cdn/cdn-standard-rules-engine) Remember to test thoroughly in a staging environment before applying changes to production, especially when dealing with security headers. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•3w ago

<@1314567457892995113> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

ACuriousProgrammerOP•3w ago

@kapa.ai can i just use nitro to extend the headers not overwrite them?

kapa.ai•3w ago

Let me check the knowledge base for you again. One moment! :books: ---------------------- Yes, you can use Nitro to extend the headers without completely overwriting them. Nitro provides a way to modify headers at runtime using the routeRules configuration. Here's how you can extend the existing headers: 1. First, create a nitro.config.ts file in your project root if you haven't already. 2. In this file, you can use the routeRules option to add or modify headers. Here's an example of how you can extend the Content-Security-Policy header:

import { defineNitroConfig } from 'nitropack'

export default defineNitroConfig({
  routeRules: {
    '/**': {
      headers: {
        'Content-Security-Policy': (headers) => {
          const existingCSP = headers['content-security-policy'] || ''
          const imgSrc = existingCSP.match(/img-src([^;]*)/)?.[1] || ''
          const newImgSrc = `${imgSrc} ${process.env.NUXT_PUBLIC_IMAGE_CDN}`.trim()
          return existingCSP.replace(/img-src([^;]*)/, `img-src ${newImgSrc}`)
        }
      }
    }
  }
})

import { defineNitroConfig } from 'nitropack'

export default defineNitroConfig({
  routeRules: {
    '/**': {
      headers: {
        'Content-Security-Policy': (headers) => {
          const existingCSP = headers['content-security-policy'] || ''
          const imgSrc = existingCSP.match(/img-src([^;]*)/)?.[1] || ''
          const newImgSrc = `${imgSrc} ${process.env.NUXT_PUBLIC_IMAGE_CDN}`.trim()
          return existingCSP.replace(/img-src([^;]*)/, `img-src ${newImgSrc}`)
        }
      }
    }
  }
})

This configuration does the following: - It applies to all routes ('/**'). - It retrieves the existing Content-Security-Policy header. - It extracts the existing img-src directive. - It adds the new CDN URL from the environment variable to the img-src directive. - It replaces the old img-src directive with the new one in the CSP header. This approach allows you to extend the existing headers without overwriting them completely. The Content-Security-Policy function will be called at runtime, so it will use the current value of the NUXT_PUBLIC_IMAGE_CDN environment variable. Remember to set the NUXT_PUBLIC_IMAGE_CDN environment variable in your Azure environment with the CDN URL. This method is more performant than using middleware because it's integrated into Nitro's core functionality for handling headers. Nitro Route Rules (https://nitro.unjs.io/guide/routing#route-rules) Make sure to test this configuration thoroughly in a staging environment before deploying to production, as modifying security headers can have significant implications for your application's security posture. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•3w ago

<@1314567457892995113> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

ACuriousProgrammerOP•3w ago

@kapa.ai defineNitroConfig seems to be depricated

kapa.ai•3w ago

Let me check the knowledge base for you again. One moment! :books: ---------------------- I apologize for the confusion in my previous response. You're correct to point out that there might be an issue with defineNitroConfig. Let's clarify this based on the most up-to-date information from the Nuxt documentation. In Nuxt 3, the recommended way to configure Nitro is through the nitro property in your nuxt.config.ts file. Here's how you can extend the headers using this approach:

export default defineNuxtConfig({
  nitro: {
    routeRules: {
      '/**': {
        headers: {
          'Content-Security-Policy': (headers) => {
            const existingCSP = headers['content-security-policy'] || ''
            const imgSrc = existingCSP.match(/img-src([^;]*)/)?.[1] || ''
            const newImgSrc = `${imgSrc} ${process.env.NUXT_PUBLIC_IMAGE_CDN}`.trim()
            return existingCSP.replace(/img-src([^;]*)/, `img-src ${newImgSrc}`)
          }
        }
      }
    }
  }
})

export default defineNuxtConfig({
  nitro: {
    routeRules: {
      '/**': {
        headers: {
          'Content-Security-Policy': (headers) => {
            const existingCSP = headers['content-security-policy'] || ''
            const imgSrc = existingCSP.match(/img-src([^;]*)/)?.[1] || ''
            const newImgSrc = `${imgSrc} ${process.env.NUXT_PUBLIC_IMAGE_CDN}`.trim()
            return existingCSP.replace(/img-src([^;]*)/, `img-src ${newImgSrc}`)
          }
        }
      }
    }
  }
})

This configuration achieves the same result as the previous example, but it's integrated directly into your Nuxt configuration. The nitro key in the Nuxt configuration is the correct way to set Nitro-specific options, as mentioned in the Nuxt documentation (https://nuxt.com/docs/guide/directory-structure/server#nitro-config). Thank you for bringing this to my attention. It's important to use the most current and recommended methods when working with Nuxt and Nitro. This approach should work well for extending your headers without overwriting them completely. Nuxt Server Engine Configuration (https://nuxt.com/docs/guide/directory-structure/server#nitro-config) Remember to test this configuration in a development or staging environment before applying it to production. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•3w ago

<@1314567457892995113> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

ACuriousProgrammerOP•3w ago

@kapa.ai i dont have process.env.NUXT_PUBLIC_IMAGE_CDN on build

kapa.ai•3w ago

Let me check the knowledge base for you again. One moment! :books: ---------------------- I understand your concern about not having process.env.NUXT_PUBLIC_IMAGE_CDN available at build time. This is a common scenario when dealing with environment variables that are only known at runtime, especially in cloud environments like Azure. Let's adjust our approach to handle this situation: 1. First, we need to ensure that we're using Nuxt's runtime config correctly. In your nuxt.config.ts, define the runtime config like this:

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      imageCdn: '' // This will be populated by NUXT_PUBLIC_IMAGE_CDN at runtime
    }
  },
  // ... other config
})

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      imageCdn: '' // This will be populated by NUXT_PUBLIC_IMAGE_CDN at runtime
    }
  },
  // ... other config
})

2. Then, in your Nitro route rules, we can use the useRuntimeConfig() function to access the runtime config. Here's how you can modify your nuxt.config.ts:

export default defineNuxtConfig({
  // ... other config
  nitro: {
    routeRules: {
      '/**': {
        headers: {
          'Content-Security-Policy': (headers, event) => {
            const config = useRuntimeConfig(event)
            const existingCSP = headers['content-security-policy'] || ''
            const imgSrc = existingCSP.match(/img-src([^;]*)/)?.[1] || ''
            const newImgSrc = `${imgSrc} ${config.public.imageCdn}`.trim()
            return existingCSP.replace(/img-src([^;]*)/, `img-src ${newImgSrc}`)
          }
        }
      }
    }
  }
})

export default defineNuxtConfig({
  // ... other config
  nitro: {
    routeRules: {
      '/**': {
        headers: {
          'Content-Security-Policy': (headers, event) => {
            const config = useRuntimeConfig(event)
            const existingCSP = headers['content-security-policy'] || ''
            const imgSrc = existingCSP.match(/img-src([^;]*)/)?.[1] || ''
            const newImgSrc = `${imgSrc} ${config.public.imageCdn}`.trim()
            return existingCSP.replace(/img-src([^;]*)/, `img-src ${newImgSrc}`)
          }
        }
      }
    }
  }
})

This approach has several advantages: 1. It doesn't rely on process.env being available at build time. 2. It uses Nuxt's runtime config system, which is designed to handle environment variables that are only known at runtime. 3. It will work correctly in both development and production environments. Remember to set the NUXT_PUBLIC_IMAGE_CDN environment variable in your Azure environment with the CDN URL. Nuxt will automatically populate the runtimeConfig.public.imageCdn value with this environment variable at runtime. Nuxt Runtime Config (https://nuxt.com/docs/guide/going-further/runtime-config) Nuxt Route Rules (https://nuxt.com/docs/api/configuration/nuxt-config#routerules) This solution should work even when you don't have the CDN URL available at build time. It dynamically adds the CDN URL to your Content-Security-Policy header when the application is running. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•3w ago

<@1314567457892995113> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

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how to extend nuxt security headers after build using enviroment vars?