Added plugin prototype

- Added proof of concept plugin prototype
- Added wip plugin page

example/plugins/helloworld/zoraxy_plugin/zoraxy_plugin.go

@@ -0,0 +1,186 @@
+package zoraxy_plugin
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+)
+
+/*
+	Plugins Includes.go
+
+	This file is copied from Zoraxy source code
+	You can always find the latest version under mod/plugins/includes.go
+	Usually this file are backward compatible
+*/
+
+type PluginType int
+
+const (
+	PluginType_Router    PluginType = 0 //Router Plugin, used for handling / routing / forwarding traffic
+	PluginType_Utilities PluginType = 1 //Utilities Plugin, used for utilities like Zerotier or Static Web Server that do not require interception with the dpcore
+)
+
+type CaptureRule struct {
+	CapturePath     string `json:"capture_path"`
+	IncludeSubPaths bool   `json:"include_sub_paths"`
+}
+
+type ControlStatusCode int
+
+const (
+	ControlStatusCode_CAPTURED  ControlStatusCode = 280 //Traffic captured by plugin, ask Zoraxy not to process the traffic
+	ControlStatusCode_UNHANDLED ControlStatusCode = 284 //Traffic not handled by plugin, ask Zoraxy to process the traffic
+	ControlStatusCode_ERROR     ControlStatusCode = 580 //Error occurred while processing the traffic, ask Zoraxy to process the traffic and log the error
+)
+
+type SubscriptionEvent struct {
+	EventName   string `json:"event_name"`
+	EventSource string `json:"event_source"`
+	Payload     string `json:"payload"` //Payload of the event, can be empty
+}
+
+type RuntimeConstantValue struct {
+	ZoraxyVersion string `json:"zoraxy_version"`
+	ZoraxyUUID    string `json:"zoraxy_uuid"`
+}
+
+/*
+IntroSpect Payload
+
+When the plugin is initialized with -introspect flag,
+the plugin shell return this payload as JSON and exit
+*/
+type IntroSpect struct {
+	/* Plugin metadata */
+	ID            string     `json:"id"`             //Unique ID of your plugin, recommended using your own domain in reverse like com.yourdomain.pluginname
+	Name          string     `json:"name"`           //Name of your plugin
+	Author        string     `json:"author"`         //Author name of your plugin
+	AuthorContact string     `json:"author_contact"` //Author contact of your plugin, like email
+	Description   string     `json:"description"`    //Description of your plugin
+	URL           string     `json:"url"`            //URL of your plugin
+	Type          PluginType `json:"type"`           //Type of your plugin, Router(0) or Utilities(1)
+	VersionMajor  int        `json:"version_major"`  //Major version of your plugin
+	VersionMinor  int        `json:"version_minor"`  //Minor version of your plugin
+	VersionPatch  int        `json:"version_patch"`  //Patch version of your plugin
+
+	/*
+
+		Endpoint Settings
+
+	*/
+
+	/*
+		Global Capture Settings
+
+		Once plugin is enabled these rules always applies, no matter which HTTP Proxy rule it is enabled on
+		This captures the whole traffic of Zoraxy
+
+		Notes: Will raise a warning on the UI when the user enables the plugin on a HTTP Proxy rule
+	*/
+	GlobalCapturePath    []CaptureRule `json:"global_capture_path"`    //Global traffic capture path of your plugin
+	GlobalCaptureIngress string        `json:"global_capture_ingress"` //Global traffic capture ingress path of your plugin (e.g. /g_handler)
+
+	/*
+		Always Capture Settings
+
+		Once the plugin is enabled on a given HTTP Proxy rule,
+		these always applies
+	*/
+	AlwaysCapturePath    []CaptureRule `json:"always_capture_path"`    //Always capture path of your plugin when enabled on a HTTP Proxy rule (e.g. /myapp)
+	AlwaysCaptureIngress string        `json:"always_capture_ingress"` //Always capture ingress path of your plugin when enabled on a HTTP Proxy rule (e.g. /a_handler)
+
+	/*
+		Dynamic Capture Settings
+
+		Once the plugin is enabled on a given HTTP Proxy rule,
+		the plugin can capture the request and decided if the request
+		shall be handled by itself or let it pass through
+
+	*/
+	DynmaicCaptureIngress string `json:"capture_path"` //Traffic capture path of your plugin (e.g. /capture)
+	DynamicHandleIngress  string `json:"handle_path"`  //Traffic handle path of your plugin (e.g. /handler)
+
+	/* UI Path for your plugin */
+	UIPath string `json:"ui_path"` //UI path of your plugin (e.g. /ui), will proxy the whole subpath tree to Zoraxy Web UI as plugin UI
+
+	/* Subscriptions Settings */
+	SubscriptionPath    string            `json:"subscription_path"`    //Subscription event path of your plugin (e.g. /notifyme), a POST request with SubscriptionEvent as body will be sent to this path when the event is triggered
+	SubscriptionsEvents map[string]string `json:"subscriptions_events"` //Subscriptions events of your plugin, see Zoraxy documentation for more details
+}
+
+/*
+ServeIntroSpect Function
+
+This function will check if the plugin is initialized with -introspect flag,
+if so, it will print the intro spect and exit
+
+Place this function at the beginning of your plugin main function
+*/
+func ServeIntroSpect(pluginSpect *IntroSpect) {
+	if len(os.Args) > 1 && os.Args[1] == "-introspect" {
+		//Print the intro spect and exit
+		jsonData, _ := json.MarshalIndent(pluginSpect, "", " ")
+		fmt.Println(string(jsonData))
+		os.Exit(0)
+	}
+}
+
+/*
+ConfigureSpec Payload
+
+Zoraxy will start your plugin with -configure flag,
+the plugin shell read this payload as JSON and configure itself
+by the supplied values like starting a web server at given port
+that listens to 127.0.0.1:port
+*/
+type ConfigureSpec struct {
+	Port         int                  `json:"port"`          //Port to listen
+	RuntimeConst RuntimeConstantValue `json:"runtime_const"` //Runtime constant values
+	//To be expanded
+}
+
+/*
+RecvExecuteConfigureSpec Function
+
+This function will read the configure spec from Zoraxy
+and return the ConfigureSpec object
+
+Place this function after ServeIntroSpect function in your plugin main function
+*/
+func RecvConfigureSpec() (*ConfigureSpec, error) {
+	for i, arg := range os.Args {
+		if strings.HasPrefix(arg, "-configure=") {
+			var configSpec ConfigureSpec
+			if err := json.Unmarshal([]byte(arg[11:]), &configSpec); err != nil {
+				return nil, err
+			}
+			return &configSpec, nil
+		} else if arg == "-configure" {
+			var configSpec ConfigureSpec
+			var nextArg string
+			if len(os.Args) > i+1 {
+				nextArg = os.Args[i+1]
+				if err := json.Unmarshal([]byte(nextArg), &configSpec); err != nil {
+					return nil, err
+				}
+			} else {
+				return nil, fmt.Errorf("No port specified after -configure flag")
+			}
+			return &configSpec, nil
+		}
+	}
+	return nil, fmt.Errorf("No -configure flag found")
+}
+
+/*
+ServeAndRecvSpec Function
+
+This function will serve the intro spect and return the configure spec
+See the ServeIntroSpect and RecvConfigureSpec for more details
+*/
+func ServeAndRecvSpec(pluginSpect *IntroSpect) (*ConfigureSpec, error) {
+	ServeIntroSpect(pluginSpect)
+	return RecvConfigureSpec()
+}