evcc-io/util/jq/jq.go

52 lines
1.3 KiB
Go

package jq
import (
"context"
"encoding/json"
"errors"
"fmt"
"github.com/itchyny/gojq"
)
// Query executes a compiled jq query against given json. It expects a single result only.
func Query(query *gojq.Query, input []byte) (any, error) {
return QueryContext(context.Background(), query, input)
}
// QueryContext executes a compiled jq query against given json, aborting when ctx is done.
// It expects a single result only. Use this instead of Query whenever the query originates
// from an untrusted source, since jq is turing-complete and evaluation may not terminate.
func QueryContext(ctx context.Context, query *gojq.Query, input []byte) (any, error) {
var j any
if err := json.Unmarshal(input, &j); err != nil {
return j, err
}
iter := query.RunWithContext(ctx, j)
v, ok := iter.Next()
if !ok {
return nil, errors.New("jq: empty result")
}
if err, ok := v.(error); ok {
// halt/halt_error do not terminate the iterator by themselves
var he *gojq.HaltError
if errors.As(err, &he) {
return nil, errors.New("jq: query halted")
}
if ctxErr := ctx.Err(); ctxErr != nil {
return nil, fmt.Errorf("jq: %w", ctxErr)
}
return nil, fmt.Errorf("jq: query failed: %v", err)
}
if _, ok := iter.Next(); ok {
return nil, errors.New("jq: too many results")
}
return v, nil
}