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Allow for updating values using queries and wildcards
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This commit allows for updating values for more "complex" paths like:

	friends.#(last="Murphy")#.last

This is allowed because GJSON now tracks the origin positions of all
results (tidwall/gjson#222).

This new ability is limited to updating values only. Setting new
values that previously did not exist, or deleting values will
return an error.
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@tidwall
tidwall committed Sep 4, 2021
1 parent a2a89c2 commit 0bc94ab
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Showing 2 changed files with 124 additions and 62 deletions.
118 changes: 90 additions & 28 deletions sjson.go
View file
Expand Up @@ -3,6 +3,8 @@ package sjson

import (
jsongo "encoding/json"
"errors"
"sort"
"strconv"
"unsafe"

Expand Down Expand Up @@ -41,7 +43,16 @@ type pathResult struct {
more bool // there is more path to parse
}

func parsePath(path string) (pathResult, error) {
func isSimpleChar(ch byte) bool {
switch ch {
case '|', '#', '@', '*', '?':
return false
default:
return true
}
}

func parsePath(path string) (res pathResult, simple bool) {
var r pathResult
if len(path) > 0 && path[0] == ':' {
r.force = true
Expand All @@ -53,12 +64,10 @@ func parsePath(path string) (pathResult, error) {
r.gpart = path[:i]
r.path = path[i+1:]
r.more = true
return r, nil
return r, true
}
if path[i] == '*' || path[i] == '?' {
return r, &errorType{"wildcard characters not allowed in path"}
} else if path[i] == '#' {
return r, &errorType{"array access character not allowed in path"}
if !isSimpleChar(path[i]) {
return r, false
}
if path[i] == '\\' {
// go into escape mode. this is a slower path that
Expand All @@ -84,13 +93,9 @@ func parsePath(path string) (pathResult, error) {
r.gpart = string(gpart)
r.path = path[i+1:]
r.more = true
return r, nil
} else if path[i] == '*' || path[i] == '?' {
return r, &errorType{
"wildcard characters not allowed in path"}
} else if path[i] == '#' {
return r, &errorType{
"array access character not allowed in path"}
return r, true
} else if !isSimpleChar(path[i]) {
return r, false
}
epart = append(epart, path[i])
gpart = append(gpart, path[i])
Expand All @@ -99,12 +104,12 @@ func parsePath(path string) (pathResult, error) {
// append the last part
r.part = string(epart)
r.gpart = string(gpart)
return r, nil
return r, true
}
}
r.part = path
r.gpart = path
return r, nil
return r, true
}

func mustMarshalString(s string) bool {
Expand Down Expand Up @@ -502,7 +507,7 @@ type sliceHeader struct {
func set(jstr, path, raw string,
stringify, del, optimistic, inplace bool) ([]byte, error) {
if path == "" {
return nil, &errorType{"path cannot be empty"}
return []byte(jstr), &errorType{"path cannot be empty"}
}
if !del && optimistic && isOptimisticPath(path) {
res := gjson.Get(jstr, path)
Expand Down Expand Up @@ -530,7 +535,7 @@ func set(jstr, path, raw string,
}
return jbytes[:sz], nil
}
return nil, nil
return []byte(jstr), nil
}
buf := make([]byte, 0, sz)
buf = append(buf, jstr[:res.Index]...)
Expand All @@ -545,26 +550,83 @@ func set(jstr, path, raw string,
}
// parse the path, make sure that it does not contain invalid characters
// such as '#', '?', '*'
paths := make([]pathResult, 0, 4)
r, err := parsePath(path)
if err != nil {
return nil, err
var paths []pathResult
r, simple := parsePath(path)
if simple {
paths = append(paths, r)
for r.more {
r, simple = parsePath(r.path)
if !simple {
break
}
paths = append(paths, r)
}
}
paths = append(paths, r)
for r.more {
if r, err = parsePath(r.path); err != nil {
return nil, err
if !simple {
if del {
return []byte(jstr),
errors.New("cannot delete value from a complex path")
}
paths = append(paths, r)
return setComplexPath(jstr, path, raw, stringify)
}

njson, err := appendRawPaths(nil, jstr, paths, raw, stringify, del)
if err != nil {
return nil, err
return []byte(jstr), err
}
return njson, nil
}

func setComplexPath(jstr, path, raw string, stringify bool) ([]byte, error) {
res := gjson.Get(jstr, path)
if !res.Exists() || !(res.Index != 0 || len(res.Indexes) != 0) {
return []byte(jstr), errors.New("no values found at path")
}
if res.Index != 0 {
njson := []byte(jstr[:res.Index])
if stringify {
njson = appendStringify(njson, raw)
} else {
njson = append(njson, raw...)
}
njson = append(njson, jstr[res.Index+len(res.Raw):]...)
jstr = string(njson)
}
if len(res.Indexes) > 0 {
type val struct {
index int
res gjson.Result
}
vals := make([]val, 0, len(res.Indexes))
res.ForEach(func(_, vres gjson.Result) bool {
vals = append(vals, val{res: vres})
return true
})
if len(res.Indexes) != len(vals) {
return []byte(jstr),
errors.New("could not set value due to index mismatch")
}
for i := 0; i < len(res.Indexes); i++ {
vals[i].index = res.Indexes[i]
}
sort.SliceStable(vals, func(i, j int) bool {
return vals[i].index > vals[j].index
})
for _, val := range vals {
vres := val.res
index := val.index
njson := []byte(jstr[:index])
if stringify {
njson = appendStringify(njson, raw)
} else {
njson = append(njson, raw...)
}
njson = append(njson, jstr[index+len(vres.Raw):]...)
jstr = string(njson)
}
}
return []byte(jstr), nil
}

// SetOptions sets a json value for the specified path with options.
// A path is in dot syntax, such as "name.last" or "age".
// This function expects that the json is well-formed, and does not validate.
Expand Down
68 changes: 34 additions & 34 deletions sjson_test.go
View file
Expand Up @@ -7,43 +7,10 @@ import (
"testing"
"time"

"github.com/tidwall/pretty"

"github.com/tidwall/gjson"
"github.com/tidwall/pretty"
)

func TestInvalidPaths(t *testing.T) {
var err error
_, err = SetRaw(`{"hello":"world"}`, "", `"planet"`)
if err == nil || err.Error() != "path cannot be empty" {
t.Fatalf("expecting '%v', got '%v'", "path cannot be empty", err)
}
_, err = SetRaw("", "name.last.#", "")
if err == nil || err.Error() != "array access character not allowed in path" {
t.Fatalf("expecting '%v', got '%v'", "array access character not allowed in path", err)
}
_, err = SetRaw("", "name.last.\\1#", "")
if err == nil || err.Error() != "array access character not allowed in path" {
t.Fatalf("expecting '%v', got '%v'", "array access character not allowed in path", err)
}
_, err = SetRaw("", "name.las?t", "")
if err == nil || err.Error() != "wildcard characters not allowed in path" {
t.Fatalf("expecting '%v', got '%v'", "wildcard characters not allowed in path", err)
}
_, err = SetRaw("", "name.la\\s?t", "")
if err == nil || err.Error() != "wildcard characters not allowed in path" {
t.Fatalf("expecting '%v', got '%v'", "wildcard characters not allowed in path", err)
}
_, err = SetRaw("", "name.las*t", "")
if err == nil || err.Error() != "wildcard characters not allowed in path" {
t.Fatalf("expecting '%v', got '%v'", "wildcard characters not allowed in path", err)
}
_, err = SetRaw("", "name.las\\a*t", "")
if err == nil || err.Error() != "wildcard characters not allowed in path" {
t.Fatalf("expecting '%v', got '%v'", "wildcard characters not allowed in path", err)
}
}

const (
setRaw = 1
setBool = 2
Expand Down Expand Up @@ -335,5 +302,38 @@ func TestIssue36(t *testing.T) {
}
}

var example = `
{
"name": {"first": "Tom", "last": "Anderson"},
"age":37,
"children": ["Sara","Alex","Jack"],
"fav.movie": "Deer Hunter",
"friends": [
{"first": "Dale", "last": "Murphy", "age": 44, "nets": ["ig", "fb", "tw"]},
{"first": "Roger", "last": "Craig", "age": 68, "nets": ["fb", "tw"]},
{"first": "Jane", "last": "Murphy", "age": 47, "nets": ["ig", "tw"]}
]
}
`

func TestIndex(t *testing.T) {
path := `friends.#(last="Murphy").last`
json, err := Set(example, path, "Johnson")
if err != nil {
t.Fatal(err)
}
if gjson.Get(json, "friends.#.last").String() != `["Johnson","Craig","Murphy"]` {
t.Fatal("mismatch")
}
}

func TestIndexes(t *testing.T) {
path := `friends.#(last="Murphy")#.last`
json, err := Set(example, path, "Johnson")
if err != nil {
t.Fatal(err)
}
if gjson.Get(json, "friends.#.last").String() != `["Johnson","Craig","Johnson"]` {
t.Fatal("mismatch")
}
}

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