fix for when payload ends with terminating boundary

fixes #48

Author: robrichard

src/__test__/PatchResolver.spec.js

@@ -7,12 +7,7 @@ global.TextDecoder = TextDecoder;
 function getMultiPartResponse(data, boundary) {
     const json = JSON.stringify(data);
 
-    return [
-        'Content-Type: application/json',
-        '',
-        json,
-        `--${boundary}\r\n`,
-    ].join('\r\n');
+    return ['Content-Type: application/json', '', json, `--${boundary}\r\n`].join('\r\n');
 }
 
 describe('PathResolver', function () {
@@ -193,6 +188,117 @@ describe('PathResolver', function () {
                 resolver.handleChunk(chunk2b);
                 expect(onResponse.mock.calls[0][0]).toEqual([chunk2Data]);
             });
+            it('should work when final chunk ends with terminating boundary', function () {
+                const onResponse = jest.fn();
+                const resolver = new PatchResolver({
+                    onResponse,
+                    boundary,
+                });
+
+                resolver.handleChunk(`\r\n--${boundary}\r\n`);
+
+                expect(onResponse).not.toHaveBeenCalled();
+
+                resolver.handleChunk(chunk1);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk1Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk2);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk2Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk3);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk3Data]);
+
+                onResponse.mockClear();
+                const chunk4FinalBoundary = getMultiPartResponse(chunk4Data, `${boundary}--`);
+                resolver.handleChunk(chunk4FinalBoundary);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk4Data]);
+            });
+
+            it('should work with preamble', function () {
+                const onResponse = jest.fn();
+                const resolver = new PatchResolver({
+                    onResponse,
+                    boundary,
+                });
+
+                resolver.handleChunk(`This is some preamble data that should be ignored\r\n`);
+                resolver.handleChunk(`\r\n--${boundary}\r\n`);
+
+                expect(onResponse).not.toHaveBeenCalled();
+
+                resolver.handleChunk(chunk1);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk1Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk2);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk2Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk3);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk3Data]);
+
+                onResponse.mockClear();
+                const chunk4FinalBoundary = getMultiPartResponse(chunk4Data, `${boundary}--`);
+                resolver.handleChunk(chunk4FinalBoundary);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk4Data]);
+            });
+            it('should work with epilogue', function () {
+                const onResponse = jest.fn();
+                const resolver = new PatchResolver({
+                    onResponse,
+                    boundary,
+                });
+
+                resolver.handleChunk(`\r\n--${boundary}\r\n`);
+
+                expect(onResponse).not.toHaveBeenCalled();
+
+                resolver.handleChunk(chunk1);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk1Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk2);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk2Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk3);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk3Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk4);
+                resolver.handleChunk(`This is some epilogue data that should be ignored\r\n`);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk4Data]);
+            });
+            it('should work with epilogue after chunk with terminating boundary', function () {
+                const onResponse = jest.fn();
+                const resolver = new PatchResolver({
+                    onResponse,
+                    boundary,
+                });
+
+                resolver.handleChunk(`\r\n--${boundary}\r\n`);
+
+                expect(onResponse).not.toHaveBeenCalled();
+
+                resolver.handleChunk(chunk1);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk1Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk2);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk2Data]);
+
+                onResponse.mockClear();
+                resolver.handleChunk(chunk3);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk3Data]);
+
+                onResponse.mockClear();
+                const chunk4FinalBoundary = getMultiPartResponse(chunk4Data, `${boundary}--`);
+                resolver.handleChunk(chunk4FinalBoundary);
+                resolver.handleChunk(`This is some epilogue data that should be ignored\r\n`);
+                expect(onResponse.mock.calls[0][0]).toEqual([chunk4Data]);
+            });
         });
     }
 });

src/parseMultipartHttp.js

@@ -2,6 +2,10 @@ function getDelimiter(boundary) {
     return `\r\n--${boundary}\r\n`;
 }
 
+function getClosingDelimiter(boundary) {
+    return `\r\n--${boundary}--\r\n`;
+}
+
 function splitWithRest(string, delim) {
     const index = string.indexOf(delim);
     if (index < 0) {
@@ -13,7 +17,7 @@ function splitWithRest(string, delim) {
 export function parseMultipartHttp(buffer, boundary, previousParts = [], isPreamble = true) {
     const delimiter = getDelimiter(boundary);
 
-    const [region, next] = splitWithRest(buffer, delimiter);
+    let [region, next] = splitWithRest(buffer, delimiter);
 
     if (region !== undefined && (region.length || region.trim() === '') && isPreamble) {
         if (next && next.length) {
@@ -24,21 +28,24 @@ export function parseMultipartHttp(buffer, boundary, previousParts = [], isPream
         }
     }
 
-    if (!(region && region.length)) {
-        // we need more things
-        return {
-            newBuffer: buffer,
-            parts: previousParts,
-            isPreamble
-        };
+    if (!region) {
+        const closingDelimiter = getClosingDelimiter(boundary);
+        [region, next] = splitWithRest(buffer, closingDelimiter);
+
+        if (!region) {
+            // we need more things
+            return {
+                newBuffer: buffer,
+                parts: previousParts,
+                isPreamble,
+            };
+        }
     }
 
     let [_headers, body] = splitWithRest(region, '\r\n\r\n');
 
     // remove trailing boundary things
-    body = body
-        .replace(delimiter + '\r\n', '')
-        .replace(delimiter + '--\r\n', '');
+    body = body.replace(delimiter + '\r\n', '').replace(delimiter + '--\r\n', '');
 
     const payload = JSON.parse(body);
     const parts = [...previousParts, payload];