jsonpath

src/udi/handlers/sve/sve.go

@@ -7,6 +7,8 @@ import (
   "strings"
   "regexp"
   "fmt"
+  "encoding/json"
+  "github.com/oliveagle/jsonpath"
   "udi/config"
   "udi/handlers/handler"
   "udi/database"
@@ -19,11 +21,13 @@ type SingleValueExtractorHandler struct {
   ready bool
   config localConfig
   payloadRegex *regexp.Regexp
+  payloadJsonpath *jsonpath.Compiled
   dbh *database.DatabaseHandle
 }
 
 const TOPIC_SEL = "topic"
-const PAYLOAD_SEL = "payload"
+const PAYLOAD_REGEX_SEL = "payload-regex"
+const PAYLOAD_JSONPATH_SEL = "payload-jsonpath"
 const PAYLOAD_FULL_SEL = "payload-full"
 const CONSTANT_SEL = "constant"
 
@@ -60,8 +64,20 @@ func NewSveHandler(config config.HandlerConfigT) handler.Handler {
   } else {
     t.payloadRegex = nil
   }
+  payloadJsonpath := config.Attributes["payloadJsonpath"]
+  if payloadJsonpath != "" {
+    j, err := jsonpath.Compile(payloadJsonpath)
+    if err != nil {
+      log.Printf("Unable to compile jsonpath %s", payloadJsonpath)
+      t.payloadJsonpath = nil
+    } else {
+      t.payloadJsonpath = j
+    }
+  } else {
+    t.payloadJsonpath = nil
+  }
 
-  if config.Attributes["deviceFrom"] != TOPIC_SEL && config.Attributes["deviceFrom"] != PAYLOAD_SEL && config.Attributes["deviceFrom"] != CONSTANT_SEL {
+  if config.Attributes["deviceFrom"] != TOPIC_SEL && config.Attributes["deviceFrom"] != PAYLOAD_REGEX_SEL && config.Attributes["deviceFrom"] != CONSTANT_SEL {
     log.Printf("Error: invalid value %s for deviceFrom", config.Attributes["deviceFrom"])
     return t
   }
@@ -77,13 +93,13 @@ func NewSveHandler(config config.HandlerConfigT) handler.Handler {
   // empty device is valid
   localConfig.device = config.Attributes["device"]
 
-  if config.Attributes["valueFrom"] != TOPIC_SEL && config.Attributes["valueFrom"] != PAYLOAD_SEL && config.Attributes["valueFrom"] != PAYLOAD_FULL_SEL {
+  if config.Attributes["valueFrom"] != PAYLOAD_REGEX_SEL && config.Attributes["valueFrom"] != PAYLOAD_JSONPATH_SEL && config.Attributes["valueFrom"] != PAYLOAD_FULL_SEL {
     log.Printf("Error: invalid value %s for valueFrom", config.Attributes["valueFrom"])
     return t
   }
   localConfig.valueFrom = config.Attributes["valueFrom"]
 
-  if config.Attributes["valueFrom"] != PAYLOAD_FULL_SEL {
+  if config.Attributes["valueFrom"] == PAYLOAD_REGEX_SEL {
     valuePart, err2 := strconv.Atoi(config.Attributes["valuePart"])
     if err2 != nil {
       log.Printf("Error: unable to convert valuePart to number: %s", err2)
@@ -92,7 +108,7 @@ func NewSveHandler(config config.HandlerConfigT) handler.Handler {
     localConfig.valuePart = valuePart
   }
 
-  if config.Attributes["unitFrom"] != TOPIC_SEL && config.Attributes["unitFrom"] != PAYLOAD_SEL && config.Attributes["unitFrom"] != CONSTANT_SEL {
+  if config.Attributes["unitFrom"] != TOPIC_SEL && config.Attributes["unitFrom"] != PAYLOAD_REGEX_SEL && config.Attributes["unitFrom"] != CONSTANT_SEL {
     log.Printf("Error: invalid value %s for unitFrom", config.Attributes["unitFrom"])
     return t
   }
@@ -152,7 +168,7 @@ func (self *SingleValueExtractorHandler) Handle(message handler.MessageT) {
       return
     }
     measurement.Device = subTopics[self.config.devicePart]
-  case PAYLOAD_SEL:
+  case PAYLOAD_REGEX_SEL:
     if self.payloadRegex == nil {
       lost("no payloadRegex defined, devicePart can't be used", message)
       return
@@ -172,22 +188,29 @@ func (self *SingleValueExtractorHandler) Handle(message handler.MessageT) {
   variable.Variable = ""
 
   switch self.config.valueFrom {
-  case TOPIC_SEL:
-    if self.config.valuePart >= len(subTopics) {
-      lost("valuePart out of range", message)
-      return
-    }
-    variable.Value = subTopics[self.config.valuePart]
-  case PAYLOAD_SEL:
+  case PAYLOAD_REGEX_SEL:
     if self.payloadRegex == nil {
       lost("no payloadRegex defined, valuePart can't be used", message)
       return
     }
-    if self.config.valuePart >= len(subTopics) {
+    if self.config.valuePart >= len(payloadMatches) {
       lost("valuePart out of range", message)
       return
     }
     variable.Value = payloadMatches[self.config.valuePart]
+  case PAYLOAD_JSONPATH_SEL:
+    if self.payloadJsonpath == nil {
+      lost("no payloadJsonpath defined, valuePart can't be used", message)
+      return
+    }
+    var jsonData interface{}
+    json.Unmarshal([]byte(message.Payload), &jsonData)
+    result, err := self.payloadJsonpath.Lookup(jsonData)
+    if err != nil {
+      lost(fmt.Sprintf("jsonpath error: %s", err), message)
+      return
+    }
+    variable.Value = result
   case PAYLOAD_FULL_SEL:
     variable.Value = message.Payload
   }
@@ -199,7 +222,7 @@ func (self *SingleValueExtractorHandler) Handle(message handler.MessageT) {
       return
     }
     variable.Unit = subTopics[self.config.unitPart]
-  case PAYLOAD_SEL:
+  case PAYLOAD_REGEX_SEL:
     if self.payloadRegex == nil {
       lost("no payloadRegex defined, unitPart can't be used", message)
       return