Merge pull request #257 from pmezard/pretty-print-queries

query: add DumpQuery to expand string query and format them as JSON

query.go

@@ -11,6 +11,7 @@ package bleve
 
 import (
 	"encoding/json"
+	"fmt"
 
 	"github.com/blevesearch/bleve/index"
 	"github.com/blevesearch/bleve/search"
@@ -209,3 +210,90 @@ func ParseQuery(input []byte) (Query, error) {
 	}
 	return nil, ErrorUnknownQueryType
 }
+
+// expandQuery traverses the input query tree and returns a new tree where
+// query string queries have been expanded into base queries. Returned tree may
+// reference queries from the input tree or new queries.
+func expandQuery(m *IndexMapping, query Query) (Query, error) {
+	var expand func(query Query) (Query, error)
+	var expandSlice func(queries []Query) ([]Query, error)
+
+	expandSlice = func(queries []Query) ([]Query, error) {
+		expanded := []Query{}
+		for _, q := range queries {
+			exp, err := expand(q)
+			if err != nil {
+				return nil, err
+			}
+			expanded = append(expanded, exp)
+		}
+		return expanded, nil
+	}
+
+	expand = func(query Query) (Query, error) {
+		switch query.(type) {
+		case *queryStringQuery:
+			q := query.(*queryStringQuery)
+			parsed, err := parseQuerySyntax(q.Query, m)
+			if err != nil {
+				return nil, fmt.Errorf("could not parse '%s': %s", q.Query, err)
+			}
+			return expand(parsed)
+		case *conjunctionQuery:
+			q := *query.(*conjunctionQuery)
+			children, err := expandSlice(q.Conjuncts)
+			if err != nil {
+				return nil, err
+			}
+			q.Conjuncts = children
+			return &q, nil
+		case *disjunctionQuery:
+			q := *query.(*disjunctionQuery)
+			children, err := expandSlice(q.Disjuncts)
+			if err != nil {
+				return nil, err
+			}
+			q.Disjuncts = children
+			return &q, nil
+		case *booleanQuery:
+			q := *query.(*booleanQuery)
+			var err error
+			q.Must, err = expand(q.Must)
+			if err != nil {
+				return nil, err
+			}
+			q.Should, err = expand(q.Should)
+			if err != nil {
+				return nil, err
+			}
+			q.MustNot, err = expand(q.MustNot)
+			if err != nil {
+				return nil, err
+			}
+			return &q, nil
+		case *phraseQuery:
+			q := *query.(*phraseQuery)
+			children, err := expandSlice(q.TermQueries)
+			if err != nil {
+				return nil, err
+			}
+			q.TermQueries = children
+			return &q, nil
+		default:
+			return query, nil
+		}
+	}
+	return expand(query)
+}
+
+// DumpQuery returns a string representation of the query tree, where query
+// string queries have been expanded into base queries. The output format is
+// meant for debugging purpose and may change in the future.
+func DumpQuery(m *IndexMapping, query Query) (string, error) {
+	q, err := expandQuery(m, query)
+	if err != nil {
+		return "", err
+	}
+	data, err := json.MarshalIndent(q, "", "  ")
+	return string(data), err
+}

query_test.go

@@ -11,6 +11,7 @@ package bleve
 
 import (
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -232,3 +233,54 @@ func TestQueryValidate(t *testing.T) {
 		}
 	}
 }
+
+func TestDumpQuery(t *testing.T) {
+	mapping := &IndexMapping{}
+	q := NewQueryStringQuery("+water -light beer")
+	s, err := DumpQuery(mapping, q)
+	if err != nil {
+		t.Fatal(err)
+	}
+	s = strings.TrimSpace(s)
+	wanted := strings.TrimSpace(`{
+  "must": {
+    "conjuncts": [
+      {
+        "match": "water",
+        "boost": 1,
+        "prefix_length": 0,
+        "fuzziness": 0
+      }
+    ],
+    "boost": 1
+  },
+  "should": {
+    "disjuncts": [
+      {
+        "match": "beer",
+        "boost": 1,
+        "prefix_length": 0,
+        "fuzziness": 0
+      }
+    ],
+    "boost": 1,
+    "min": 1
+  },
+  "must_not": {
+    "disjuncts": [
+      {
+        "match": "light",
+        "boost": 1,
+        "prefix_length": 0,
+        "fuzziness": 0
+      }
+    ],
+    "boost": 1,
+    "min": 0
+  },
+  "boost": 1
+}`)
+	if wanted != s {
+		t.Fatalf("query:\n%s\ndiffers from expected:\n%s", s, wanted)
+	}
+}