feat: Add an AI-Proxy Wasm plugin (#921)

Co-authored-by: 澄潭 <zty98751@alibaba-inc.com>

plugins/wasm-go/extensions/ai-proxy/util/http.go

@@ -0,0 +1,36 @@
+package util
+
+import "github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
+
+const (
+	HeaderContentType = "Content-Type"
+
+	MimeTypeTextPlain       = "text/plain"
+	MimeTypeApplicationJson = "application/json"
+)
+
+func SendResponse(statusCode uint32, contentType, body string) error {
+	return proxywasm.SendHttpResponse(statusCode, CreateHeaders(HeaderContentType, contentType), []byte(body), -1)
+}
+
+func CreateHeaders(kvs ...string) [][2]string {
+	headers := make([][2]string, 0, len(kvs)/2)
+	for i := 0; i < len(kvs); i += 2 {
+		headers = append(headers, [2]string{kvs[i], kvs[i+1]})
+	}
+	return headers
+}
+
+func OverwriteRequestHost(host string) error {
+	if originHost, err := proxywasm.GetHttpRequestHeader(":authority"); err == nil {
+		_ = proxywasm.ReplaceHttpRequestHeader("X-ENVOY-ORIGINAL-HOST", originHost)
+	}
+	return proxywasm.ReplaceHttpRequestHeader(":authority", host)
+}
+
+func OverwriteRequestPath(path string) error {
+	if originPath, err := proxywasm.GetHttpRequestHeader(":path"); err == nil {
+		_ = proxywasm.ReplaceHttpRequestHeader("X-ENVOY-ORIGINAL-PATH", originPath)
+	}
+	return proxywasm.ReplaceHttpRequestHeader(":path", path)
+}