Make clients gracefully handle mismatched 304 responses

kornelski · kornelski · commit 7894244310c5 · 2018-12-30T17:20:35.000Z
https://github.com/lukechilds/cacheable-request/issues/28
diff --git a/index.js b/index.js
@@ -488,7 +488,11 @@ module.exports = class CachePolicy {
         if (!matches) {
             return {
                 policy: new this.constructor(request, response),
-                modified: true,
+                // Client receiving 304 without body, even if it's invalid/mismatched has no option
+                // but to reuse a cached body. We don't have a good way to tell clients to do
+                // error recovery in such case.
+                modified: response.status != 304,
+                matches: false,
             }
         }
 
@@ -507,6 +511,7 @@ module.exports = class CachePolicy {
         return {
             policy: new this.constructor(request, newResponse, {shared: this._isShared, cacheHeuristic: this._cacheHeuristic, immutableMinTimeToLive: this._immutableMinTtl, trustServerDate: this._trustServerDate}),
             modified: false,
+            matches: true,
         };
     }
 };

Original file line number	Diff line number	Diff line change
`@@ -488,7 +488,11 @@ module.exports = class CachePolicy {`
`488`	`488`	`if (!matches) {`
`489`	`489`	`return {`
`490`	`490`	`policy: new this.constructor(request, response),`
`491`		`- modified: true,`
	`491`	`+ // Client receiving 304 without body, even if it's invalid/mismatched has no option`
	`492`	`+ // but to reuse a cached body. We don't have a good way to tell clients to do`
	`493`	`+ // error recovery in such case.`
	`494`	`+ modified: response.status != 304,`
	`495`	`+ matches: false,`
`492`	`496`	`}`
`493`	`497`	`}`
`494`	`498`
`@@ -507,6 +511,7 @@ module.exports = class CachePolicy {`
`507`	`511`	`return {`
`508`	`512`	`policy: new this.constructor(request, newResponse, {shared: this._isShared, cacheHeuristic: this._cacheHeuristic, immutableMinTimeToLive: this._immutableMinTtl, trustServerDate: this._trustServerDate}),`
`509`	`513`	`modified: false,`
	`514`	`+ matches: true,`
`510`	`515`	`};`
`511`	`516`	`}`
`512`	`517`	`};`