rclone/vendor/github.com/jmespath/go-jmespath/cmd/jpgo/main.go
2017-03-05 10:24:46 +00:00

97 lines
2.1 KiB
Go

/*Basic command line interface for debug and testing purposes.
Examples:
Only print the AST for the expression:
jp.go -ast "foo.bar.baz"
Evaluate the JMESPath expression against JSON data from a file:
jp.go -input /tmp/data.json "foo.bar.baz"
This program can also be used as an executable to the jp-compliance
runner (github.com/jmespath/jmespath.test).
*/
package main
import (
"flag"
"fmt"
"io/ioutil"
"os"
)
import (
"encoding/json"
"github.com/jmespath/go-jmespath"
)
func errMsg(msg string, a ...interface{}) int {
fmt.Fprintf(os.Stderr, msg, a...)
fmt.Fprintln(os.Stderr)
return 1
}
func run() int {
astOnly := flag.Bool("ast", false, "Print the AST for the input expression and exit.")
inputFile := flag.String("input", "", "Filename containing JSON data to search. If not provided, data is read from stdin.")
flag.Parse()
args := flag.Args()
if len(args) != 1 {
fmt.Fprintf(os.Stderr, "Usage:\n\n")
flag.PrintDefaults()
return errMsg("\nError: expected a single argument (the JMESPath expression).")
}
expression := args[0]
parser := jmespath.NewParser()
parsed, err := parser.Parse(expression)
if err != nil {
if syntaxError, ok := err.(jmespath.SyntaxError); ok {
return errMsg("%s\n%s\n", syntaxError, syntaxError.HighlightLocation())
}
return errMsg("%s", err)
}
if *astOnly {
fmt.Println("")
fmt.Printf("%s\n", parsed)
return 0
}
var inputData []byte
if *inputFile != "" {
inputData, err = ioutil.ReadFile(*inputFile)
if err != nil {
return errMsg("Error loading file %s: %s", *inputFile, err)
}
} else {
// If an input data file is not provided then we read the
// data from stdin.
inputData, err = ioutil.ReadAll(os.Stdin)
if err != nil {
return errMsg("Error reading from stdin: %s", err)
}
}
var data interface{}
json.Unmarshal(inputData, &data)
result, err := jmespath.Search(expression, data)
if err != nil {
return errMsg("Error executing expression: %s", err)
}
toJSON, err := json.MarshalIndent(result, "", " ")
if err != nil {
return errMsg("Error serializing result to JSON: %s", err)
}
fmt.Println(string(toJSON))
return 0
}
func main() {
os.Exit(run())
}