Add Plugin de-graphql (#303)

plugins/wasm-go/extensions/de-graphql/config/degraphql_config.go

@@ -0,0 +1,199 @@
+// Copyright (c) 2022 Alibaba Group Holding Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"errors"
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
+	"net/url"
+	"regexp"
+	"strings"
+)
+
+const (
+	DefaultEndpoint          string = "/graphql"
+	DefaultConnectionTimeout uint32 = 5000
+)
+
+var gqlVariableRegex = regexp.MustCompile(`\$(\w+)\s*:\s*(String|Float|Int|Boolean)(!?)`)
+
+type VariableType string
+
+const (
+	StringType  VariableType = "String"
+	IntType     VariableType = "Int"
+	FloatType   VariableType = "Float"
+	BooleanType VariableType = "Boolean"
+)
+
+type Variable struct {
+	name  string
+	typ   VariableType
+	blank bool
+	value string
+}
+
+type DeGraphQLConfig struct {
+	client    wrapper.HttpClient
+	gql       string
+	endpoint  string
+	timeout   uint32
+	variables []Variable
+}
+
+func (d *DeGraphQLConfig) SetEndpoint(endpoint string) error {
+	endpoint = strings.TrimSpace(endpoint)
+	if endpoint == "" {
+		d.endpoint = DefaultEndpoint
+	} else {
+		d.endpoint = endpoint
+	}
+	return nil
+}
+
+func (d *DeGraphQLConfig) GetEndpoint() string {
+	return d.endpoint
+}
+
+func (d *DeGraphQLConfig) GetTimeout() uint32 {
+	return d.timeout
+}
+
+func (d *DeGraphQLConfig) SetTimeout(timeout uint32) {
+	if timeout <= 0 {
+		d.timeout = DefaultConnectionTimeout
+	} else {
+		d.timeout = timeout
+	}
+}
+
+func (d *DeGraphQLConfig) SetClient(client wrapper.HttpClient) {
+	d.client = client
+}
+
+func (d *DeGraphQLConfig) GetClient() wrapper.HttpClient {
+	return d.client
+}
+
+func (d *DeGraphQLConfig) SetGql(gql string) error {
+	if strings.TrimSpace(gql) == "" {
+		return errors.New("gql can't be empty")
+	}
+	d.gql = gql
+	d.variables = make([]Variable, 0)
+	matches := gqlVariableRegex.FindAllStringSubmatch(d.gql, -1)
+	if len(matches) > 0 {
+		for _, subMatch := range matches {
+			variable := Variable{}
+			variable.name = subMatch[1]
+			switch subMatch[2] {
+			case "String":
+				variable.typ = StringType
+			case "Float":
+				variable.typ = FloatType
+			case "Int":
+				variable.typ = IntType
+			case "Boolean":
+				variable.typ = BooleanType
+			}
+			variable.blank = subMatch[3] != "!"
+			d.variables = append(d.variables, variable)
+		}
+
+	}
+	return nil
+}
+
+func (d *DeGraphQLConfig) GetGql() string {
+	return d.gql
+}
+
+func (d *DeGraphQLConfig) GetVersion() string {
+	return "1.0.0"
+}
+
+func (d *DeGraphQLConfig) ParseGqlFromUrl(requestUrl string) (string, error) {
+	if strings.TrimSpace(requestUrl) == "" {
+		return "", errors.New("request url can't be empty")
+	}
+
+	url, _ := url.Parse(requestUrl)
+
+	queryValues := url.Query()
+	values := make(map[string]string, len(queryValues))
+	for k, v := range queryValues {
+		var v1 string
+		if len(v) > 1 {
+			v1 = strings.Join(v, ",")
+		} else {
+			v1 = v[0]
+		}
+		values[k] = v1
+	}
+
+	variables := make([]Variable, 0, len(d.variables))
+	for _, variable := range d.variables {
+		val, ok := values[variable.name]
+		// TODO validate variable type and blank
+		if ok {
+			variables = append(variables, Variable{
+				name:  variable.name,
+				typ:   variable.typ,
+				blank: variable.blank,
+				value: val,
+			})
+		}
+	}
+
+	var build strings.Builder
+
+	// write query
+	build.WriteString("{\"query\":")
+	build.WriteString("\"")
+	build.WriteString(getJsonStr(d.gql))
+	build.WriteString("\"")
+
+	// write varialbes
+	if len(variables) > 0 {
+		index := 0
+		build.WriteString(",")
+		build.WriteString("\"variables\":{")
+		for _, variable := range variables {
+			build.WriteString("\"")
+			build.WriteString(variable.name)
+			build.WriteString("\":")
+			if variable.typ == StringType {
+				build.WriteString("\"")
+				build.WriteString(getJsonStr(variable.value))
+				build.WriteString("\"")
+			} else {
+				build.WriteString(variable.value)
+			}
+			if index < len(variables)-1 {
+				build.WriteString(",")
+			}
+			index++
+		}
+		build.WriteString("}")
+	}
+
+	build.WriteString("}")
+	return build.String(), nil
+}
+
+func getJsonStr(str string) string {
+	d := strings.ReplaceAll(str, "\"", "\\\"")
+	return strings.ReplaceAll(d, "\n", "\\n")
+}