feat: get response body in http call callback (#75)

Author: spacewander

src/http/ngx_http_wasm_api.c

@@ -410,14 +410,17 @@ proxy_log(int32_t log_level, int32_t addr, int32_t size)
 
 
 int32_t
-proxy_get_buffer_bytes(int32_t type, int32_t start, int32_t length,
+proxy_get_buffer_bytes(int32_t type, int32_t start, int32_t size,
                        int32_t addr, int32_t size_addr)
 {
     ngx_log_t            *log;
     const u_char         *data;
     int32_t               len;
     const ngx_str_t      *conf;
 
+    ngx_http_request_t      *r;
+    ngx_http_wasm_ctx_t     *ctx;
+
     log = ngx_http_wasm_get_log();
 
     switch (type) {
@@ -427,10 +430,35 @@ proxy_get_buffer_bytes(int32_t type, int32_t start, int32_t length,
         len = conf->len;
         break;
 
+    case PROXY_BUFFER_TYPE_HTTP_CALL_RESPONSE_BODY:
+        must_get_req(r);
+        ctx = ngx_http_wasm_get_module_ctx(r);
+        data = ctx->call_resp_body->data;
+        len = ctx->call_resp_body->len;
+        break;
+
     default:
         return PROXY_RESULT_UNIMPLEMENTED;
     }
 
+    if (len == 0) {
+        return PROXY_RESULT_NOT_FOUND;
+    }
+
+    if (type != PROXY_BUFFER_TYPE_PLUGIN_CONFIGURATION) {
+        /* configuration is fetched as a whole */
+        if (start < 0 || size <= 0 || start >= len) {
+            return PROXY_RESULT_BAD_ARGUMENT;
+        }
+
+        if (start + size > len) {
+            size = len - start;
+        }
+
+        data = data + start;
+        len = size;
+    }
+
     return ngx_http_wasm_copy_to_wasm(log, data, len, addr, size_addr);
 }
 

src/http/ngx_http_wasm_module.c

@@ -728,7 +728,7 @@ ngx_http_wasm_on_http_call_resp(ngx_http_wasm_plugin_ctx_t *hwp_ctx, ngx_http_re
                           &proxy_on_http_call_response,
                           false, NGX_WASM_PARAM_I32_I32_I32_I32_I32,
                           hwp_ctx->id, ctx->callout_id,
-                          n_header, 0, 0);
+                          n_header, body == NULL ? 0 : body->len, 0);
 
     ngx_http_wasm_set_state(NULL);
 

t/WASM.pm

@@ -77,6 +77,10 @@ add_block_preprocessor(sub {
                     local body = ngx.req.get_body_data()
                     ngx.log(ngx.WARN, "hit with body ", body)
                 end
+
+                if ngx.var.arg_body then
+                    ngx.print(ngx.var.arg_body)
+                end
             }
         }
     }

t/http_call_callback.t

@@ -78,3 +78,90 @@ location /t {
 }
 --- error_log
 callback err: error status returned by host: not found
+
+
+
+=== TEST 4: get body, no body
+--- config
+location /t {
+    content_by_lua_block {
+        local json = require("cjson")
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("plugin", "t/testdata/http_call/main.go.wasm"))
+        local conf = {host = "127.0.0.1:1980", action = "body"}
+        local ctx = assert(wasm.on_configure(plugin, json.encode(conf)))
+        assert(wasm.on_http_request_headers(ctx))
+    }
+}
+--- error_log
+get bodySize 0
+error status returned by host: not found
+
+
+
+=== TEST 5: get body
+--- config
+location /t {
+    content_by_lua_block {
+        local json = require("cjson")
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("plugin", "t/testdata/http_call/main.go.wasm"))
+        local conf = {host = "127.0.0.1:1980", action = "body", path = "/?body=helloworld"}
+        for _, e in ipairs({
+            {0, 2},
+            {1, 1},
+            {1, 2},
+            {0, 10},
+            {1, 9},
+            {8, 2},
+            {9, 1},
+            {1, 10},
+        }) do
+            conf.start = e[1]
+            conf.size = e[2]
+            local ctx = assert(wasm.on_configure(plugin, json.encode(conf)))
+            assert(wasm.on_http_request_headers(ctx))
+        end
+    }
+}
+--- grep_error_log eval
+qr/get body \[\w+\]/
+--- grep_error_log_out
+get body [he]
+get body [e]
+get body [el]
+get body [helloworld]
+get body [elloworld]
+get body [ld]
+get body [d]
+get body [elloworld]
+
+
+
+=== TEST 6: get body, bad cases
+--- config
+location /t {
+    content_by_lua_block {
+        local json = require("cjson")
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("plugin", "t/testdata/http_call/main.go.wasm"))
+        local conf = {host = "127.0.0.1:1980", action = "body", path = "/?body=helloworld"}
+        for _, e in ipairs({
+            {-1, 2},
+            {1, 0},
+            {1, -1},
+            {10, 2},
+        }) do
+            conf.start = e[1]
+            conf.size = e[2]
+            local ctx = assert(wasm.on_configure(plugin, json.encode(conf)))
+            assert(wasm.on_http_request_headers(ctx))
+        end
+    }
+}
+--- error_log
+[error]
+--- grep_error_log eval
+qr/error status returned by host: bad argument/
+--- grep_error_log_out eval
+"error status returned by host: bad argument\n" x 4

t/testdata/http_call/main.go

@@ -82,6 +82,18 @@ func (ctx *httpContext) dispatchHttpCall(elem *fastjson.Value) {
 				proxywasm.LogWarnf("get header %s: %s", h[0], h[1])
 			}
 		}
+	case "body":
+		ctx.callback = func(numHeaders int, bodySize int, numTrailers int) {
+			proxywasm.LogWarnf("get bodySize %d", bodySize)
+			start := elem.GetInt("start")
+			size := elem.GetInt("size")
+			body, err := proxywasm.GetHttpCallResponseBody(start, size)
+			if err != nil {
+				proxywasm.LogErrorf("callback err: %v", err)
+				return
+			}
+			proxywasm.LogWarnf("get body [%s]", string(body))
+		}
 	}
 
 	hs := [][2]string{}