readme and comment

examples/http_body_chunk/README.md

@@ -1,16 +1,28 @@
 ## http_body
 
-this example demonstrates how to perform operation on a request body, chunk by chunk.
+This example demonstrates how to perform operations on a request body, chunk by chunk.
 
-# TODO!
-To modify the request:
+Reading the received body chunk by chunk, it looks for the string "pattern" inside the body. If it finds it, a 403 response is returned providing the number of the chunk where the pattern was found. Logs are printed every time a chunk is received providing also the size of the read chunk.
+
+Build and run the example:
+```bash
+$ make build.example name=http_body_chunk
+$ make run name=http_body_chunk
 ```
-$ curl -XPUT localhost:18000 --data '[initial body]' -H "buffer-operation: prepend"
-[this is prepended body][initial body]
 
-$ curl -XPUT localhost:18000 --data '[initial body]' -H "buffer-operation: append"
-[initial body][this is appended body]
+Perform a request with a body containing the string "pattern":
+```bash
+$ head -c 700000 /dev/urandom | base64 > /tmp/file.txt && echo "pattern" >> /tmp/file.txt && curl 'localhost:18000/anything' -d @/tmp/file.txt
+pattern found in chunk: 2
+```
 
-$ curl -XPUT localhost:18000 --data '[initial body]' -H "buffer-operation: replace"
-[this is replaced body]
+Logs generated:
+```
+wasm log: OnHttpRequestBody called. BodySize: 114532, totalRequestBodyReadSize: 0, endOfStream: false
+wasm log: read chunk size: 114532
+wasm log: OnHttpRequestBody called. BodySize: 114532, totalRequestBodyReadSize: 114532, endOfStream: false
+wasm log: OnHttpRequestBody called. BodySize: 933343, totalRequestBodyReadSize: 114532, endOfStream: true
+wasm log: read chunk size: 818811
+wasm log: pattern found in chunk: 2
+wasm log: local 403 response sent
 ```

proxywasm/proxytest/http_test.go

@@ -85,7 +85,8 @@ func TestBodyBuffering(t *testing.T) {
 			name:     "buffered",
 			buffered: true,
 			action:   types.ActionPause,
-			logged:   "1111122222",
+			// The first chunk has been buffered, therefore it will be retrieved when calling GetHttpRequestBody at the end of stream.
+			logged: "1111122222",
 		},
 		{
 			name:     "unbuffered",