package main

import (
  "github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
  "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
  "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
  "github.com/tidwall/gjson"
)

func main() {
  wrapper.SetCtx(
    // Plugin name
    "my-plugin",
    // A custom function for parsing plugin configurations
    wrapper.ParseConfigBy(parseConfig),
    // A custom function for processing request headers
    wrapper.ProcessRequestHeadersBy(onHttpRequestHeaders),
  )
}

// Custom plugin configuration
type MyConfig struct {
  mockEnable bool
}

// Plugin configurations set in the console with YAML format will be converted to JSON. So we just need to parse config data from JSON.
func parseConfig(json gjson.Result, config *MyConfig, log wrapper.Log) error {
  // Get the configuration property and set to the config object.
  config.mockEnable = json.Get("mockEnable").Bool()
  return nil
}

func onHttpRequestHeaders(ctx wrapper.HttpContext, config MyConfig, log wrapper.Log) types.Action {
  proxywasm.AddHttpRequestHeader("hello", "world")
  if config.mockEnable {
    proxywasm.SendHttpResponse(200, nil, []byte("hello world"), -1)
  }
  return types.ActionContinue
}

package main

import (
  "github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
  "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
  "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
)

func main() {
  wrapper.SetCtx(
    "hello-world",
    wrapper.ProcessRequestHeadersBy(onHttpRequestHeaders),
  )
}

type MyConfig struct {}

func onHttpRequestHeaders(ctx wrapper.HttpContext, config MyConfig, log wrapper.Log) types.Action {
  proxywasm.SendHttpResponse(200, nil, []byte("hello world"), -1)
  return types.ActionContinue
}

package main

import (
  "errors"
  "net/http"
  "strings"
  "github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
  "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
  "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
  "github.com/tidwall/gjson"
)

func main() {
  wrapper.SetCtx(
    "http-call",
    wrapper.ParseConfigBy(parseConfig),
    wrapper.ProcessRequestHeadersBy(onHttpRequestHeaders),
  )
}

type MyConfig struct {
  // The client used to initiate an HTTP request
  client      wrapper.HttpClient
  // Request URL
  requestPath string
  // Use this key when extracting token header from the service response and setting a header to the request. The value is configurable.
  tokenHeader string
}

func parseConfig(json gjson.Result, config *MyConfig, log wrapper.Log) error {
  config.tokenHeader = json.Get("tokenHeader").String()
  if config.tokenHeader == "" {
    return errors.New("missing tokenHeader in config")
  }
  config.requestPath = json.Get("requestPath").String()
  if config.requestPath == "" {
    return errors.New("missing requestPath in config")
  }
  serviceSource := json.Get("serviceSource").String()
  // If serviceSource is set to "ip" or "dns", serviceName shall be specified when creating the service.
  // If serviceSource is set to "nacos" or "k8s", serviceName shall be set to the original name specified when registering the service.
  serviceName := json.Get("serviceName").String()
  servicePort := json.Get("servicePort").Int()
  if serviceName == "" || servicePort == 0 {
    return errors.New("invalid service config")
  }
  switch serviceSource {
  case "k8s":
    namespace := json.Get("namespace").String()
    config.client = wrapper.NewClusterClient(wrapper.K8sCluster{
      ServiceName: serviceName,
      Namespace:   namespace,
      Port:        servicePort,
    })
    return nil
  case "nacos":
    namespace := json.Get("namespace").String()
    config.client = wrapper.NewClusterClient(wrapper.NacosCluster{
      ServiceName: serviceName,
      NamespaceID: namespace,
      Port:        servicePort,
    })
    return nil
  case "ip":
    config.client = wrapper.NewClusterClient(wrapper.StaticIpCluster{
      ServiceName: serviceName,
      Port:        servicePort,
    })
    return nil
  case "dns":
    domain := json.Get("domain").String()
    config.client = wrapper.NewClusterClient(wrapper.DnsCluster{
      ServiceName: serviceName,
      Port:        servicePort,
      Domain:      domain,
    })
    return nil
  default:
    return errors.New("unknown service source: " + serviceSource)
  }
}

func onHttpRequestHeaders(ctx wrapper.HttpContext, config MyConfig, log wrapper.Log) types.Action {
  // Use the Get function of the client to initiate an HTTP Get request.
  // The timeout parameter is omitted here, whose default value is 500ms.
  config.client.Get(config.requestPath, nil,
    // A callback function which will be called asynchronously when receiving the response.
    func(statusCode int, responseHeaders http.Header, responseBody []byte) {
      // Process the response with a status code other than 200.
      if statusCode != http.StatusOK {
        log.Errorf("http call failed, status: %d", statusCode)
        proxywasm.SendHttpResponse(http.StatusInternalServerError, nil,
          []byte("http call failed"), -1)
        return
      }
      // Print out the status code and response body
      log.Infof("get status: %d, response body: %s", statusCode, responseBody)
      // Extract token value from the response header and set the header of the original request
      token := responseHeaders.Get(config.tokenHeader)
      if token != "" {
        proxywasm.AddHttpRequestHeader(config.tokenHeader, token)
      }
      // Resume the original request processing workflow. Continue the process, so the request can be forwarded to the upstream.
      proxywasm.ResumeHttpRequest()
    })
  // We need to wait for the callback to finish its process.
  // Return Pause action here to pause the request processing workflow, which can be resumed by a ResumeHttpRequest call.
  return types.ActionPause
}