support basic json filtering and selection

weed/query/json/query_json.go

@@ -1,5 +1,107 @@
 package json
 
-func QueryJson(jsonLine string, query string) (jsonOutput string) {
-	return jsonLine
+import (
+	"strconv"
+
+	"github.com/chrislusf/seaweedfs/weed/query/sqltypes"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/match"
+)
+
+type Query struct {
+	Field string
+	Op    string
+	Value string
+}
+
+func QueryJson(jsonLine string, projections []string, query Query) (passedFilter bool, values []sqltypes.Value) {
+	if filterJson(jsonLine, query) {
+		passedFilter = true
+		fields := gjson.GetMany(jsonLine, projections...)
+		for _, f := range fields {
+			values = append(values, sqltypes.MakeTrusted(sqltypes.Type(f.Type), sqltypes.StringToBytes(f.Raw)))
+		}
+		return
+	}
+	return false, nil
+}
+
+func filterJson(jsonLine string, query Query) bool{
+
+	value := gjson.Get(jsonLine, query.Field)
+
+	// copied from gjson.go queryMatches() function
+	rpv := query.Value
+
+	if !value.Exists() {
+		return false
+	}
+	if query.Op == "" {
+		// the query is only looking for existence, such as:
+		//   friends.#(name)
+		// which makes sure that the array "friends" has an element of
+		// "name" that exists
+		return true
+	}
+	switch value.Type {
+	case gjson.String:
+		switch query.Op {
+		case "=":
+			return value.Str == rpv
+		case "!=":
+			return value.Str != rpv
+		case "<":
+			return value.Str < rpv
+		case "<=":
+			return value.Str <= rpv
+		case ">":
+			return value.Str > rpv
+		case ">=":
+			return value.Str >= rpv
+		case "%":
+			return match.Match(value.Str, rpv)
+		case "!%":
+			return !match.Match(value.Str, rpv)
+		}
+	case gjson.Number:
+		rpvn, _ := strconv.ParseFloat(rpv, 64)
+		switch query.Op {
+		case "=":
+			return value.Num == rpvn
+		case "!=":
+			return value.Num != rpvn
+		case "<":
+			return value.Num < rpvn
+		case "<=":
+			return value.Num <= rpvn
+		case ">":
+			return value.Num > rpvn
+		case ">=":
+			return value.Num >= rpvn
+		}
+	case gjson.True:
+		switch query.Op {
+		case "=":
+			return rpv == "true"
+		case "!=":
+			return rpv != "true"
+		case ">":
+			return rpv == "false"
+		case ">=":
+			return true
+		}
+	case gjson.False:
+		switch query.Op {
+		case "=":
+			return rpv == "false"
+		case "!=":
+			return rpv != "false"
+		case "<":
+			return rpv == "true"
+		case "<=":
+			return true
+		}
+	}
+	return false
+
 }

weed/query/json/query_json_test.go

@@ -58,7 +58,7 @@ func TestGjson(t *testing.T) {
 	projections := []string{"quiz","fruit"}
 
 	gjson.ForEachLine(data, func(line gjson.Result) bool{
-		println(line.String())
+		println(line.Raw)
 		println("+++++++++++")
 		results := gjson.GetMany(line.Raw, projections...)
 		for _, result := range results {
@@ -71,3 +71,66 @@ func TestGjson(t *testing.T) {
 
 
 }
+
+func TestJsonQueryRow(t *testing.T) {
+
+	data := `
+	{
+		"fruit": "Bl\"ue",
+		"size": 6,
+		"quiz": "green"
+	}
+
+`
+	selections := []string{"fruit", "size"}
+
+	isFiltered, values := QueryJson(data, selections, Query{
+		Field: "quiz",
+		Op:    "=",
+		Value: "green",
+	})
+
+	if !isFiltered {
+		t.Errorf("should have been filtered")
+	}
+
+	if values == nil {
+		t.Errorf("values should have been returned")
+	}
+
+	buf := ToJson(nil, selections, values)
+	println(string(buf))
+
+}
+
+func TestJsonQueryNumber(t *testing.T) {
+
+	data := `
+	{
+		"fruit": "Bl\"ue",
+		"size": 6,
+		"quiz": "green"
+	}
+
+`
+	selections := []string{"fruit", "quiz"}
+
+	isFiltered, values := QueryJson(data, selections, Query{
+		Field: "size",
+		Op:    ">=",
+		Value: "6",
+	})
+
+	if !isFiltered {
+		t.Errorf("should have been filtered")
+	}
+
+	if values == nil {
+		t.Errorf("values should have been returned")
+	}
+
+	buf := ToJson(nil, selections, values)
+	println(string(buf))
+
+}
+

weed/query/json/seralize.go

@@ -0,0 +1,17 @@
+package json
+
+import "github.com/chrislusf/seaweedfs/weed/query/sqltypes"
+
+func ToJson(buf []byte, selections []string, values []sqltypes.Value) []byte {
+	buf = append(buf, '{')
+	for i, value := range values {
+		if i > 0 {
+			buf = append(buf, ',')
+		}
+		buf = append(buf, selections[i]...)
+		buf = append(buf, ':')
+		buf = append(buf, value.Raw()...)
+	}
+	buf = append(buf, '}')
+	return buf
+}