From 27ac9ba48974d495a2674f82eeaaa75327b9fda9 Mon Sep 17 00:00:00 2001
From: Tom Howard <tom.howard@greater.com.au>
Date: Mon, 27 Jun 2022 11:44:56 +1000
Subject: [PATCH] feat(content-parser): content parsers can now access previous
 implementations

---
 src/augment-options.ts       | 10 +++++---
 src/test/operations.steps.ts |  7 +++---
 src/waychaser.ts             | 48 ++++++++++++++++++++----------------
 3 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/src/augment-options.ts b/src/augment-options.ts
index a3a4ead9..787ca8a6 100644
--- a/src/augment-options.ts
+++ b/src/augment-options.ts
@@ -12,12 +12,14 @@ export function augmentOptions<BaseContent, AdditionalContent>(
     handlers: baseHandlers,
     defaultHandlers: baseDefaultHandlers,
     headers: baseHeaders,
+    contentParser: baseContentParser,
     ...baseOther
   } = baseOptions
   const {
     handlers: additionalHandlers,
     defaultHandlers: additionalDefaultHandlers,
     headers: additionalHeaders,
+    contentParser: additionalContentParser,
     ...additionalOther
   } = additionalOptions || {}
 
@@ -32,7 +34,9 @@ export function augmentOptions<BaseContent, AdditionalContent>(
     ...(additionalDefaultHandlers || baseDefaultHandlers || [])
   ])
 
-  const finalOptions = {
+  const mergedContentParser = additionalContentParser ? (response: Response) => additionalContentParser(response, baseContentParser) : baseContentParser
+
+  return {
     ...baseOther,
     ...additionalOther,
     defaultHandlers: mergedHandlers,
@@ -40,7 +44,7 @@ export function augmentOptions<BaseContent, AdditionalContent>(
     headers: {
       ...baseHeaders,
       ...additionalHeaders
-    }
+    },
+    contentParser: mergedContentParser
   }
-  return finalOptions
 }
diff --git a/src/test/operations.steps.ts b/src/test/operations.steps.ts
index a72b94b7..d09c8489 100644
--- a/src/test/operations.steps.ts
+++ b/src/test/operations.steps.ts
@@ -2,7 +2,7 @@ import { expect } from 'chai'
 import { DataTable } from '@cucumber/cucumber'
 import logger from './logger'
 import { binding, given, then, when } from 'cucumber-tsflow';
-import { Validator, waychaser, WayChaserProblem, WayChaserResponse } from '../waychaser'
+import { ContentParser, Validator, waychaser, WayChaserProblem, WayChaserResponse } from '../waychaser'
 import {
     uniqueNamesGenerator,
     adjectives,
@@ -908,13 +908,12 @@ export class OperationSteps {
 
     @given('waychaser has a custom parser for 404s')
     public async waychaserHasACustomParserFor404s() {
-        const existingContentParser = this.waychaser.currentDefaults.contentParser;
         this.waychaser = this.waychaser.defaults({
-            contentParser: async (response: Response) => {
+            contentParser: async (response: Response, contentParser: ContentParser) => {
                 return response.status === 404 ? new ProblemDocument({
                     'title': "Not found",
                     'type': 'https://waychaser.io/not-found'
-                }) : existingContentParser(response);
+                }) : contentParser(response);
             }
         })
     };
diff --git a/src/waychaser.ts b/src/waychaser.ts
index dc16e314..106d09fb 100644
--- a/src/waychaser.ts
+++ b/src/waychaser.ts
@@ -333,6 +333,8 @@ export type HandlerSpec = {
 
 export type Stopper = () => void
 
+export type ContentParser = (response: Response, contentParser?: ContentParser) => Promise<unknown | ProblemDocument | undefined>
+
 export type WayChaserOptions<ValidatorContent = null> = RequestInit & {
   fetch: typeof fetch
   handlers: Array<HandlerSpec>
@@ -340,7 +342,7 @@ export type WayChaserOptions<ValidatorContent = null> = RequestInit & {
   preInterceptors: Array<(uriOrRequest, updateOptions, stopper) => void>
   postInterceptors: Array<<InterceptorContent>(response: (WayChaserResponse<InterceptorContent>), stop: Stopper) => void>
   postErrorInterceptors: Array<(error: WayChaserProblem | Error, stopper: Stopper) => void>
-  contentParser: (response: Response) => Promise<unknown | ProblemDocument | undefined>
+  contentParser: ContentParser
   parameters?: Record<string, unknown>
   validator?: Validator<ValidatorContent>
 }
@@ -458,27 +460,31 @@ export async function _waychaser<Content>(
     updateOptions
   )
 
-  // TODO allow lazy loading of the content 
-  const content = await mergedOptions.contentParser(baseResponse)
-  // content is
-  // 1. unknown, 
-  // 2. a post response client side Problem Document,
-  // 3. a server side ProblemDocument, or
-  // 4. undefined
-
-
   try {
-    const response = WayChaserResponse.create(baseResponse, content, defaultOptions, mergedOptions)
-
-    stop = false
-    for (const interceptor of updateOptions.postInterceptors) {
-      interceptor(response, () => (stop = true))
-      if (stop) {
-        break
+    try {
+      // TODO allow lazy loading of the content 
+      const content = await mergedOptions.contentParser(baseResponse)
+      // content is
+      // 1. unknown, 
+      // 4. undefined
+      const response = WayChaserResponse.create(baseResponse, content, defaultOptions, mergedOptions)
+
+      stop = false
+      for (const interceptor of updateOptions.postInterceptors) {
+        interceptor(response, () => (stop = true))
+        if (stop) {
+          break
+        }
       }
+      return response
+    }
+    catch(error){
+      throw error instanceof ProblemDocument ? new WayChaserProblem({
+          response: new WayChaserResponse({ handlers: mergedOptions.defaultHandlers, defaultOptions, baseResponse, content: error, parameters: mergedOptions.parameters }),
+          problem: error,
+        }) : error;
     }
-    return response
-  } catch (error) {
+  } catch(error) {
     stop = false
     for (const interceptor of updateOptions.postErrorInterceptors) {
       interceptor(error, () => (stop = true))
@@ -524,7 +530,7 @@ const wayChaserDefaults: WayChaserOptions = {
           return contentType === 'application/problem+json' ? Object.assign(new ProblemDocument(jsonContent), jsonContent) : jsonContent;
         }
         catch (error) {
-          return new ProblemDocument({
+          throw new ProblemDocument({
             type: "https://waychaser.io/invalid-json",
             title: "JSON response could not be parsed",
             detail: `The response document with content type '${contentType}' could not be parsed as json`,
@@ -532,7 +538,7 @@ const wayChaserDefaults: WayChaserOptions = {
           })
         }
       }
-      return new ProblemDocument({
+      throw new ProblemDocument({
         type: "https://waychaser.io/unsupported-content-type",
         title: "The response has an unsupported content type",
         detail: `The response document has a content type of '${contentType}' which is not supported`,