How do I get this to work?
s, _ := url.QueryUnescape("%22%7B%5C%22sessionId%5C%22%3A%5C%225331b937-7b55-4c2d-798a-25e574a7e8af%5C%22%2C%5C%22userId%5C%22%3A2%2C%5C%22userName%5C%22%3A%5C%22datami_op%5C%22%2C%5C%22userEmail%5C%22%3A%5C%22datami_op%40example.com%5C%22%2C%5C%22userRoles%5C%22%3A%5B%5C%22operator%5C%22%5D%7D%22")
fmt.Println(s)
//s := "{\"sessionId\":\"5331b937-7b55-4c2d-798a-25e574a7e8af\",\"userId\":2,\"userName\":\"op\",\"userEmail\":\"datami_op#example.com\",\"userRoles\":[\"operator\"]}"
var i Info
err := json.Unmarshal([]byte(s), &i)
fmt.Println(i, err)
You can either manually remove the quoting yourself, as you have in your comment, or you could unmarshal first as a json string:
var unquote string
err := json.Unmarshal([]byte(s), &unquote)
fmt.Println(unquote, err)
var i Info
err = json.Unmarshal([]byte(unquote), &i)
fmt.Println(i, err)
I believe this does what you want:
GoPlay
Essentially you implement unmarshalJsonJson (clever name, I know)...
The function will unmarshal as a json string, then use that string in the Info unmarshalling.
func unmarshalJsonJson(inval string) (*Info, error) {
var s string
err := json.Unmarshal([]byte(inval), &s)
if err != nil {
return nil, err
}
info := new(Info)
err = json.Unmarshal([]byte(s), info)
if err != nil {
return nil, err
}
return info, nil
}
OUTPUT
main.Info{
SessionId:"5331b937-7b55-4c2d-798a-25e574a7e8af",
UserId:2,
Username:"datami_op",
Email:"datami_op#example.com",
Roles:[]string{"operator"},
}
Related
I am able to zip a file using logic similar to the zip writer seen here.
This results in an array of bytes ([]byte) being created within the bytes.Buffer object that is returned. I would just like to know if there is there any way I can upload this 'zipped' array of bytes to an API endpoint that expects a 'multipart/form-data' request body (without having to save it locally).
Supplementary information:
I have code that utilizes this when compressing a folder. I am able to successfully execute an HTTP POST request with the zip file to the endpoint with this logic.
However, this unfortunately saves zipped files in a user's local file system. I would like to try to avoid this :)
You can create multipart writer and write []byte zipped data into field with field name you like and file name like below.
func addZipFileToReq(zipped []byte) (*http.Request, error){
body := bytes.NewBuffer(nil)
writer := multipart.NewWriter(body)
part, err := writer.CreateFormFile(`fileField`, `filename`)
if err != nil {
return nil, err
}
_, err = part.Write(zipped)
if err != nil {
return nil, err
}
err = writer.Close()
if err != nil {
return nil, err
}
r, err := http.NewRequest(http.MethodPost, "https://example.com", body)
if err != nil {
return nil, err
}
r.Header.Set("Content-Type", writer.FormDataContentType())
return r, nil
}
If you want to stream-upload the zip, you should be able to do so with io.Pipe. The following is an incomplete and untested example to demonstrate the general idea. To make it work you'll need to modify it and potentially fix whatever bugs you encounter.
func UploadReader(r io.Reader) error {
req, err := http.NewRequest("POST", "<UPLOAD_URL>", r)
if err != nil {
return err
}
// TODO set necessary headers (content type, auth, etc)
res, err := http.DefaultClient.Do(req)
if err != nil {
return err
} else if res.StatusCode != 200 {
return errors.New("not ok")
}
return nil
}
func ZipDir(dir string, w io.Writer) error {
zw := zip.NewWriter(w)
defer zw.Close()
return filepath.Walk(dir, func(path string, fi os.FileInfo, err error) error {
if err != nil {
return err
}
if !fi.Mode().IsRegular() {
return nil
}
header, err := zip.FileInfoHeader(fi)
if err != nil {
return err
}
header.Name = path
header.Method = zip.Deflate
w, err := zw.CreateHeader(header)
if err != nil {
return err
}
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
if _, err := io.Copy(w, f); err != nil {
return err
}
return nil
})
}
func UploadDir(dir string) error {
r, w := io.Pipe()
ch := make(chan error)
wg := sync.WaitGroup{}
wg.Add(1)
go func() {
defer wg.Done()
defer w.Close()
if err := ZipDir(dir, w); err != nil {
ch <- err
}
}()
wg.Add(1)
go func() {
defer wg.Done()
defer r.Close()
if err := UploadReader(r); err != nil {
ch <- err
}
}()
go func() {
wg.Wait()
close(ch)
}()
return <-ch
}
I have a map like this, which I want to save/retrive from redis using redigo:
animals := map[string]bool{
"cat": true,
"dog": false,
"fox": true,
}
The length of the map may vary.
I tried these function:
func SetHash(key string, value map[string]bool) error {
conn := Pool.Get()
defer conn.Close()
_, err := conn.Do("HMSET", key, value)
if err != nil {
return fmt.Errorf("error setting key %s to %s: %v", key, value, err)
}
return err
}
func GetHash(key string) (map[string]bool, error) {
conn := Pool.Get()
defer conn.Close()
val, err := conn.Do("HGETALL", key)
if err != nil {
fmt.Errorf("error setting key %s to %s: %v", key, nil, err)
return nil, err
}
return val, err
}
But can not make GetHash correctly. I've checked the docs examples and it was not helpful. So appreciate your help to have a working example.
HMSET is deprecated, use HSET instead, no effect here though.
The map[string]bool may be flattened with AddFlat() for SetHash().
c.Do("HSET", redis.Args{}.Add("key").AddFlat(value)...)
For GetHash(), use Values(). You may use ScanStruct() to map to a struct or loop through the values to create a map dynamically.
v, err := redis.Values(c.Do("HGETALL", key))
redis.ScanStruct(v, &myStruct);
See example from redigo tests in scan_test.go.
The application is responsible for converting structured types to and from the types understood by Redis.
Flatten the map into a list of arguments:
func SetHash(key string, value map[string]bool) error {
conn := Pool.Get()
defer conn.Close()
// Create arguments: key field value [field value]...
var args = []interface{}{key}
for k, v := range value {
args = append(args, k, v)
}
_, err := conn.Do("HMSET", args...)
if err != nil {
return fmt.Errorf("error setting key %s to %v: %v", key, value, err)
}
return err
}
Convert the returned field value pairs to a map:
func GetHash(key string) (map[string]bool, error) {
conn := Pool.Get()
defer conn.Close()
values, err := redis.Strings(conn.Do("HGETALL", key))
if err != nil {
return nil, err
}
// Loop through [field value]... and parse value as bool.
m := map[string]bool{}
for i := 0; i < len(values); i += 2 {
b, err := strconv.ParseBool(value)
if err != nil {
return nil, errors.New("value not a bool")
}
m[key] = b
}
return m, nil
}
I have this function to parse HTTP results:
func (a *Admin) ResponseDecode(structName string, body io.Reader) (interface{}, error) {
content, err := ioutil.ReadAll(body)
if err != nil {
return nil, err
}
switch structName {
case "[]Cat":
var data []Cat
err = json.Unmarshal(content, &data)
if err != nil {
return nil, err
}
return data, err
case "[]Dog":
var data []Dog
err = json.Unmarshal(content, &data)
if err != nil {
return nil, err
}
return data, err
default:
log.Fatal("Can't decode " + structName)
}
return nil, nil
}
I do a type assertion after this method :
parsed, err := a.ResponseDecode("[]Cat", resp.Body)
if err != nil {
return nil, err
}
return parsed.([]Cat), nil
but how can I do to avoid the repetition of the code :
var data []Stuff
err = json.Unmarshal(content, &data)
if err != nil {
return nil, err
}
return data, err
Every time I add an object? Usually I would use generics, but this is Go. What's the good way to do that ?
You are passing in the name of the struct, and then expecting data of that type. Instead, you can simply pass the struct:
var parsed []Cat
err := a.ResponseDecode(&parsed, resp.Body)
where:
func (a *Admin) ResponseDecode(out interface{}, body io.Reader) error {
content, err := ioutil.ReadAll(body)
if err != nil {
return nil, err
}
return json.Unmarshal(content,out)
}
In fact, you can get rid of ResponseDecode function:
var parsed []Cat
err:=json.NewDecoder(body).Decode(&parsed)
Found what I was looking for here.
This function does the job :
func (a *Admin) ResponseDecode(body io.Reader, value interface{}) (interface{}, error) {
content, err := ioutil.ReadAll(body)
if err != nil {
return nil, err
}
err = json.Unmarshal(content, &value)
if err != nil {
return nil, err
}
return value, nil}
I am having a problem when appending to my slice using Golang.
Here is my code:
func MatchBeaconWithXY(w http.ResponseWriter, r *http.Request) ([]types.BeaconDataXY, error) {
context := appengine.NewContext(r)
returnBeaconData := []types.BeaconDataXY{}
beacondata, err := GetBeaconData(w, r)
if err != nil {
log.Errorf(context, "error getting beacondata %v", err)
w.WriteHeader(http.StatusInternalServerError)
return nil, err
}
for index, element := range beacondata {
q := datastore.NewQuery("physicalbeacondata").Filter("NamespaceID =", element.NamespaceID).Filter("InstanceID =", element.InstanceID)
beacondatastatic := []types.BeaconDataStatic{}
_, err := q.GetAll(context, &beacondatastatic)
if err != nil {
log.Errorf(context, "cant get query %v", err)
w.WriteHeader(http.StatusInternalServerError)
return nil, err
}
var beacondataXY = new(types.BeaconDataXY)
beacondataXY.NamespaceID = element.NamespaceID
beacondataXY.InstanceID = element.InstanceID
beacondataXY.XCoord = beacondatastatic[0].XCoord
beacondataXY.YCoord = beacondatastatic[0].YCoord
beacondataXY.Distance = element.Distance
returnBeaconData = append(returnBeaconData, beacondataXY...)
log.Infof(context, "beaondataXY tot %v", beacondataXY)
}
The beacondataxy.go contains this:
package types
type BeaconDataXY struct {
InstanceID string
NamespaceID string
XCoord float64
YCoord float64
Distance float64
}
The error message is this:
utils.go:139: cannot use beacondataXY (type *types.BeaconDataXY) as
type []types.BeaconDataXY in append
I don't really know how to handle slices in Golang, even after reading some tutorials that makes perfect sense. I'm not sure what I'm doing wrong.
I want to have an array/slice with types inside, return BeaconData is of []types. BeaconDataXY and it should contain single types of BeaconDataXY.
Thanks for all help.
EDIT:
The code now looks like this:
func MatchBeaconWithXY(w http.ResponseWriter, r *http.Request) ([]types.BeaconDataXY, error) {
context := appengine.NewContext(r)
//returnBeaconData := []types.BeaconDataXY{}
returnBeaconData := make([]types.BeaconDataXY, 1)
beacondata, err := GetBeaconData(w, r)
if err != nil {
log.Errorf(context, "error getting beacondata %v", err)
w.WriteHeader(http.StatusInternalServerError)
return nil, err
}
for _, element := range beacondata {
q := datastore.NewQuery("physicalbeacondata").Filter("NamespaceID =", element.NamespaceID).Filter("InstanceID =", element.InstanceID)
beacondatastatic := []types.BeaconDataStatic{}
_, err := q.GetAll(context, &beacondatastatic)
if err != nil {
log.Errorf(context, "cant get query %v", err)
w.WriteHeader(http.StatusInternalServerError)
return nil, err
}
var beacondataXY = types.BeaconDataXY{}
beacondataXY.NamespaceID = element.NamespaceID
beacondataXY.InstanceID = element.InstanceID
beacondataXY.XCoord = beacondatastatic[0].XCoord
beacondataXY.YCoord = beacondatastatic[0].YCoord
beacondataXY.Distance = element.Distance
returnBeaconData = append(returnBeaconData, beacondataXY)
//log.Infof(context, "beaondataXY tot %v", beacondataXY)
}
With this assignment:
var beacondataXY = new(types.BeaconDataXY)
you are creating a variable of type *types.BeaconDataXY. Just create a new BeaconDataXY like this:
var beacondataXY = types.BeaconDataXY{}
When appending to your array do it like this:
returnBeaconData = append(returnBeaconData, beacondataXY)
The "..." would assume that beacondataXY is an array but it isn't, you just want to append beacondataXY to returnBeaconData. See https://golang.org/ref/spec#Appending_and_copying_slices for an explanation of what "..." means in this context.
Try returnBeaconData = append(returnBeaconData, *beacondataXY)
new() built-in function returns a pointer, you can alternatively write:
var beacondataXY = types.BeaconDataXY{}
I want to write a file cache in Go. I am using gob encoding, and saving to a file, but my get function has some problem:
package main
import (
"encoding/gob"
"fmt"
"os"
)
var (
file = "tmp.txt"
)
type Data struct {
Expire int64
D interface{}
}
type User struct {
Id int
Name string
}
func main() {
user := User{
Id: 1,
Name: "lei",
}
err := set(file, user, 10)
if err != nil {
fmt.Println(err)
return
}
user = User{}
err = get(file, &user)
if err != nil {
fmt.Println(err)
return
}
//user not change.
fmt.Println(user)
}
func set(file string, v interface{}, expire int64) error {
f, err := os.OpenFile(file, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
if err != nil {
return err
}
defer f.Close()
//wrapper data
//save v in data.D
data := Data{
Expire: expire,
D: v,
}
gob.Register(v)
enc := gob.NewEncoder(f)
err = enc.Encode(data)
if err != nil {
return err
}
return nil
}
func get(file string, v interface{}) error {
f, err := os.OpenFile(file, os.O_RDONLY, 0600)
if err != nil {
return err
}
defer f.Close()
var data Data
dec := gob.NewDecoder(f)
err = dec.Decode(&data)
if err != nil {
return err
}
//get v
v = data.D
fmt.Println(v)
return nil
}
The get function passes interface type and I want to change the value, but not change.
http://play.golang.org/p/wV7rBH028o
In order to insert an unknown value into v of type interface{}, you need to use reflection. This is somewhat involved, but if you want to support this in full, you can see how its done by walking through the decoding process in some of the encoding packages (json, gob).
To get you started, here's a basic version of your get function using reflection. This skips a number of checks, and will only decode something that was encoded as a pointer.
func get(file string, v interface{}) error {
f, err := os.OpenFile(file, os.O_RDONLY, 0600)
if err != nil {
return err
}
defer f.Close()
rv := reflect.ValueOf(v)
if rv.Kind() != reflect.Ptr || rv.IsNil() {
panic("need a non nil pointer")
}
var data Data
dec := gob.NewDecoder(f)
err = dec.Decode(&data)
if err != nil {
return err
}
dv := reflect.ValueOf(data.D)
if dv.Kind() != reflect.Ptr {
panic("didn't decode a pointer")
}
rv.Elem().Set(dv.Elem())
return nil
}
I would actually suggest an easier way to handle this in your own code, which is to have the Get function return an interface{}. Since you will know what the possible types are at that point, you can use a type switch to assert the correct value.
An alternative approach is to return directly the value from the file:
func get(file string) (interface{}, error) {
f, err := os.OpenFile(file, os.O_RDONLY, 0600)
if err != nil {
return nil, err
}
defer f.Close()
var data Data
dec := gob.NewDecoder(f)
err = dec.Decode(&data)
if err != nil {
return nil,err
}
fmt.Println(data.D)
return data.D,nil
}
full working example: http://play.golang.org/p/178U_LVC5y