chore: refactor source image URL construction (#66)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: ascorbic

example/public/index.html

@@ -19,6 +19,14 @@ <h1 class="text-4xl mb-4">Netlify Optimized Images</h1>
     <figcaption>/.netlify/builders/ipx/f_webp,w_450/img/https://images.unsplash.com/photo-1514888286974-6c03e2ca1dba
       <figcaption>
   </figure>
+  <figure>
+    <img
+      src="/.netlify/builders/ipx/f_webp,w_450/https%3A%2F%2Fimages.unsplash.com%2Fphoto-1514888286974-6c03e2ca1dba%3Fheight%3D500%26width%3D500%26fit%3Dcrop" />
+    <figcaption>
+      /.netlify/builders/ipx/f_webp,w_450/img/https%3A%2F%2Fimages.unsplash.com%2Fphoto-1514888286974-6c03e2ca1dba%3Fheight%3D500%26width%3D500%26fit%3Dcrop
+      With query string in source
+      <figcaption>
+  </figure>
   <figure>
     <img src="/.netlify/builders/ipx/f_webp,w_146/https://www.netlify.com/img/deploy/button.svg" />
     <figcaption>/.netlify/builders/ipx/f_webp,w_146/img/https://www.netlify.com/img/deploy/button.svg
@@ -49,4 +57,4 @@ <h1 class="text-4xl mb-4">Netlify Optimized Images</h1>
 
 </body>
 
-</html>
+</html>

src/index.ts

@@ -29,19 +29,17 @@ export function createIPXHandler ({
     basePath = `${basePath}/`
   }
   const handler: Handler = async (event, _context) => {
-    const host = event.headers.host
-    const protocol = event.headers['x-forwarded-proto'] === 'https' ? 'https' : 'http'
     let domains = (opts as IPXOptions).domains || []
     const remoteURLPatterns = remotePatterns || []
     const requestEtag = event.headers['if-none-match']
-    const url = event.path.replace(basePath, '')
+    const eventPath = event.path.replace(basePath, '')
 
     // eslint-disable-next-line prefer-const
-    let [modifiers = '_', ...segments] = url.split('/')
+    let [modifiers = '_', ...segments] = eventPath.split('/')
     let id = decodeURIComponent(segments.join('/'))
 
     if (propsEncoding === 'base64') {
-      const params = decodeBase64Params(url)
+      const params = decodeBase64Params(eventPath)
       if (params.error) {
         return {
           statusCode: 400,
@@ -53,9 +51,11 @@ export function createIPXHandler ({
     }
 
     const requestHeaders: Record<string, string> = {}
-    const isLocal = !id.startsWith('http')
+    const isLocal = !id.startsWith('http://') && !id.startsWith('https://')
     if (isLocal) {
-      id = `${protocol}://${host}${id.startsWith('/') ? '' : '/'}${id}`
+      const url = new URL(event.rawUrl)
+      url.pathname = id
+      id = url.toString()
       if (event.headers.cookie) {
         requestHeaders.cookie = event.headers.cookie
       }