fix: pre-read requests prevent read/write index confusion (#113)

runner-core/src/main/java/org/apache/apisix/plugin/runner/handler/HTTPReqCallHandler.java

@@ -142,6 +142,10 @@ private void handleHttpReqCall(ChannelHandlerContext ctx, HttpRequest request) {
 
         PluginFilterChain chain = conf.getChain();
 
+        // here we pre-read parameters in the req to
+        // prevent confusion over the read/write index of the req.
+        preReadReq();
+
         // if the filter chain is empty, then return the response directly
         if (Objects.isNull(chain) || 0 == chain.getFilters().size()) {
             ChannelFuture future = ctx.writeAndFlush(currResp);
@@ -194,6 +198,14 @@ private void handleHttpReqCall(ChannelHandlerContext ctx, HttpRequest request) {
         }
     }
 
+    private void preReadReq() {
+        currReq.getHeader();
+        currReq.getPath();
+        currReq.getMethod();
+        currReq.getArgs();
+        currReq.getSourceIP();
+    }
+
     private void errorHandle(ChannelHandlerContext ctx, int code) {
         A6ErrResponse errResponse = new A6ErrResponse(code);
         ctx.writeAndFlush(errResponse);

runner-core/src/test/java/org/apache/apisix/plugin/runner/handler/ExtraInfoTest.java

@@ -204,7 +204,7 @@ void testFetchBody() {
     }
 
     @Test
-    @DisplayName("test fetch request body of extra info")
+    @DisplayName("test get vars in plugin filter")
     void testGetVarsInPluginFilter() {
         FlatBufferBuilder builder = new FlatBufferBuilder();
 
@@ -276,6 +276,9 @@ void testGetVarsInPluginFilter() {
         Assertions.assertTrue(bytes.toString().contains("server_port: 9080"));
         Assertions.assertTrue(bytes.toString().contains("content_type: application/json"));
         Assertions.assertTrue(bytes.toString().contains("body: abcd"));
+
+        // test pre-read request in HttpCallHandler
+        Assertions.assertEquals(HttpRequest.Method.GET, request.getMethod());
     }
 
 }

runner-plugin-sdk/src/main/java/org/apache/apisix/plugin/runner/HttpRequest.java

@@ -21,6 +21,7 @@
 import io.github.api7.A6.TextEntry;
 import org.apache.apisix.plugin.runner.filter.PluginFilter;
 import org.springframework.util.CollectionUtils;
+import org.springframework.util.StringUtils;
 
 import java.nio.ByteBuffer;
 import java.util.HashMap;
@@ -84,7 +85,9 @@ public String getSourceIP() {
             for (int i = 0; i < req.srcIpLength(); i++) {
                 builder.append(req.srcIp(i)).append('.');
             }
-            sourceIP = builder.substring(0, builder.length() - 1);
+            if (StringUtils.hasText(builder.toString())) {
+                sourceIP = builder.substring(0, builder.length() - 1);
+            }
         }
 
         return sourceIP;