Add regexp to where expressions

README.md

@@ -176,7 +176,7 @@ NEARBY searches a collection for objects that intersect a specified radius.
 <BR CLEAR="ALL">
 
 ### Search options
-**WHERE** - This option allows for filtering out results based on [field](#fields) values. For example<br>```nearby fleet where speed 70 +inf point 33.462 -112.268 6000``` will return only the objects in the 'fleet' collection that are within the 6 km radius **and** have a field named `speed` that is greater than `70`. <br><br>Multiple WHEREs are concatenated as **and** clauses. ```WHERE speed 70 +inf WHERE age -inf 24``` would be interpreted as *speed is over 70 <b>and</b> age is less than 24.*<br><br>The default value for a field is always `0`. Thus if you do a WHERE on the field `speed` and an object does not have that field set, the server will pretend that the object does and that the value is Zero.
+**WHERE** - This option allows for filtering out results based on [field](#fields) values. For example<br>```nearby fleet where speed 70 +inf point 33.462 -112.268 6000``` will return only the objects in the 'fleet' collection that are within the 6 km radius **and** have a field named `speed` that is greater than `70`. <br><br>Multiple WHEREs are concatenated as **and** clauses. ```WHERE speed 70 +inf WHERE age -inf 24``` would be interpreted as *speed is over 70 <b>and</b> age is less than 24.*<br><br>The default value for a field is always `0`. Thus if you do a WHERE on the field `speed` and an object does not have that field set, the server will pretend that the object does and that the value is Zero.<br><br>WHERE expressions support the `=~` operator for regex matching. It uses Go's re2 regular expression engine to match string values in fields or GeoJSON properties within objects. For example, `WHERE properties.name =~ 'truck.*'` filters objects where the 'name' property matches the pattern, and `WHERE field_name =~ 'value.*'` works similarly for fields.
 
 **MATCH** - MATCH is similar to WHERE except that it works on the object id instead of fields.<br>```nearby fleet match truck* point 33.462 -112.268 6000``` will return only the objects in the 'fleet' collection that are within the 6 km radius **and** have an object id that starts with `truck`. There can be multiple MATCH options in a single search. The MATCH value is a simple [glob pattern](https://en.wikipedia.org/wiki/Glob_(programming)).
 

internal/server/expr.go

@@ -1,6 +1,8 @@
 package server
 
 import (
+	"fmt"
+	"regexp"
 	"sync"
 
 	"github.com/tidwall/expr"
@@ -9,10 +11,12 @@
 	"github.com/tidwall/match"
 	"github.com/tidwall/tile38/internal/field"
 	"github.com/tidwall/tile38/internal/object"
+	"github.com/tidwall/tinylru"
 )
 
 type exprPool struct {
-	pool *sync.Pool
+	pool       *sync.Pool
+	regexCache tinylru.LRUG[string, *regexp.Regexp]
 }
 
 func typeForObject(o *object.Object) expr.Value {
@@ -89,6 +93,8 @@
 }
 
 func newExprPool(s *Server) *exprPool {
+	pool := &exprPool{}
+
 	ext := expr.NewExtender(
 		// ref
 		func(info expr.RefInfo, ctx *expr.Context) (expr.Value, error) {
@@ -98,6 +104,10 @@
 				if info.Ident == "this" {
 					return expr.Object(o), nil
 				}
+				// Register regex as a root function
+				if info.Ident == "regex" {
+					return expr.Function("regex"), nil
+				}
 				return objExpr(o, info)
 			} else {
 				switch v := info.Value.Value().(type) {
@@ -132,19 +142,37 @@
 		},
 		// op
 		func(info expr.OpInfo, ctx *expr.Context) (expr.Value, error) {
+			switch info.Op {
+			case expr.OpRegex:
+				field := info.Left.String()
+				pattern := info.Right.String()
+
+				re, ok := pool.regexCache.Get(pattern)
+				if !ok {
+					var err error
+					re, err = regexp.Compile(pattern)
+					if err != nil {
+						return expr.Undefined, fmt.Errorf("invalid regex pattern: %v", err)
+					}
+					pool.regexCache.Set(pattern, re)
+				}
+
+				return expr.Bool(re.MatchString(field)), nil
+			}
 			return expr.Undefined, nil
 		},
 	)
-	return &exprPool{
-		pool: &sync.Pool{
-			New: func() any {
-				ctx := &expr.Context{
-					Extender: ext,
-				}
-				return ctx
-			},
+
+	pool.pool = &sync.Pool{
+		New: func() any {
+			ctx := &expr.Context{
+				Extender: ext,
+			}
+			return ctx
 		},
 	}
+
+	return pool
 }
 
 func (p *exprPool) Get(o *object.Object) *expr.Context {

tests/keys_test.go

@@ -560,11 +560,20 @@ func keys_FIELDS_test(mc *mockServer) error {
 		Do("SCAN", "fleet", "WHERE", "hello.world", "<=", `tom`, "IDS").JSON().Str(`{"ok":true,"ids":["truck1","truck2"],"count":2,"cursor":0}`),
 		Do("SCAN", "fleet", "WHERE", "hello.world", "<", `uom`, "IDS").JSON().Str(`{"ok":true,"ids":["truck1","truck2"],"count":2,"cursor":0}`),
 		Do("SCAN", "fleet", "WHERE", "hello.world", "!=", `tom`, "IDS").JSON().Str(`{"ok":true,"ids":["truck1"],"count":1,"cursor":0}`),
+		// Test REGEX on FIELD
+		Do("SCAN", "fleet", "WHERE", "regex(hello.world, 'tom.*')", "IDS").JSON().Str(`{"ok":true,"ids":["truck2"],"count":1,"cursor":0}`),
+		Do("SCAN", "fleet", "WHERE", "regex(hello.world, 'foo.*')", "IDS").JSON().Str(`{"ok":true,"ids":[],"count":0,"cursor":0}`),
+		Do("SCAN", "fleet", "WHERE", "regex(hello.world, '(*')", "IDS").JSON().Str(`{"ok":true,"ids":[],"count":0,"cursor":0}`),
 
 		Do("SET", "fleet", "truck1", "OBJECT", `{"type":"Feature","geometry":{"type":"Point","coordinates":[-112,33]},"properties":{"speed":50},"asdf":"Adsf"}`).JSON().OK(),
 		Do("SCAN", "fleet", "WHERE", "properties.speed", ">", 49, "IDS").JSON().Str(`{"ok":true,"ids":["truck1"],"count":1,"cursor":0}`),
 		Do("SCAN", "fleet", "WHERE", "properties.speed", ">", 50, "IDS").JSON().Str(`{"ok":true,"ids":[],"count":0,"cursor":0}`),
 		Do("SCAN", "fleet", "WHERE", "properties.speed", "<", 51, "IDS").JSON().Str(`{"ok":true,"ids":["truck1","truck2"],"count":2,"cursor":0}`),
+		// Test REGEX on OBJECT properties
+		Do("SET", "fleet", "truck3", "OBJECT", `{"type":"Feature","geometry":{"type":"Point","coordinates":[-112,33]},"properties":{"name":"truck01"}}`).JSON().OK(),
+		Do("SCAN", "fleet", "WHERE", "regex(properties.name, 'truck.*')", "IDS").JSON().Str(`{"ok":true,"ids":["truck3"],"count":1,"cursor":0}`),
+		Do("SCAN", "fleet", "WHERE", "regex(properties.name, 'foo.*')", "IDS").JSON().Str(`{"ok":true,"ids":[],"count":0,"cursor":0}`),
+		Do("SCAN", "fleet", "WHERE", "regex(properties.name, '(*')", "IDS").JSON().Str(`{"ok":true,"ids":[],"count":0,"cursor":0}`),
 
 		Do("DROP", "fleet").JSON().OK(),
 		Do("SET", "fleet", "truck1", "FIELD", "speed", "50", "POINT", "-112", "33").JSON().OK(),