In golang how can I collapse an array of an object when returning to json?
I'm not sure how to properly describe this problem but here is what I'm looking for.
{
"error_code": 422,
"errors": [
"email": [
"email is required"
]
]
}
Here's my code so far
type Error struct {
Email []string `json:"email"`
}
type Response struct {
ErrorCode int `json:"error_code"`
Errors []Error `json:"errors"`
}
func handler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(422)
json.NewEncoder(w).Encode(Response{
ErrorCode: 422,
Errors: []Error{
Error{Email: []string{"email is required"}},
},
})
}
and the result is
{
"error_code": 422,
"errors": [
{
"email": [
"email is required"
]
}
]
}
Notice how errors is an array of object, how can I avoid that and directly have "email" array under "errors"?
Related
I am making a service in go that sends push notification to Expo Backend. Once the http call is made Expo respond with bellow format(according to Expo):
{
"data": [
{
"status": "error" | "ok",
"id": string, // this is the Receipt ID
// if status === "error"
"message": string,
"details": JSON
},
...
],
// only populated if there was an error with the entire request
"errors": [{
"code": number,
"message": string
}]
}
And here is an provioded example of a response:
{
"data": [
{
"status": "error",
"message": "\\\"ExponentPushToken[xxxxxxxxxxxxxxxxxxxxxx]\\\" is not a registered push notification recipient",
"details": {
"error": "DeviceNotRegistered"
}
},
{
"status": "ok",
"id": "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
}
]
}
I created struct to decode the response.Now i get a error try to decode the reponse for the "details" field, No matter what type i use in my Struct. How can i deal with that field that expo mark as "JSON"?
import (
uuid "github.com/satori/go.uuid"
)
type PushResult struct {
Errors []ErrorDetails `json:"errors,omitempty"`
Datas []DataPart `json:"data,omitempty"`
}
type ErrorDetails struct {
Code int32 `json:"code,omitempty"`
Message string `json:"message,omitempty"`
}
type DataPart struct {
Status string `json:"status,omitempty"`
ID uuid.UUID `json:"id,omitempty"`
Message string `json:"message,omitempty"`
Details string `json:"details,omitempty"` //also tried map[string]string and interface{}
}
This is the struct i am using. i also tried this by looking at the example:
type DataPart struct {
Status string `json:"status,omitempty"`
ID uuid.UUID `json:"id,omitempty"`
Message string `json:"message,omitempty"`
Details struct{
Error string `json:"error"`} `json:"details,omitempty"`
}
But every time get an error like "json: cannot unmarshal object into Go struct field DataPart.data.details"
I just created you struct using your response exemple and it worked completly fine.
Playground
That said if you wana a better way of debugging an "unmarshal error" you can unwrap it. That way you can print aditional data.
var t *json.UnmarshalTypeError
if errors.As(err, &t) {
spew.Dump(t)
}
Example -> I changed the error type to integer so I can fake the error.
OBS: Note that your "Datas" is an array and only the 1st one have an error.
Hi all I am a beginner trying to learn Go. I am trying to get the status of my EC2 instance using AWS SDK with Golang. I was successfully able to get a JSON response for my instance. I am however, having issues trying to parse the JSON response to get the instance state.
The following is how I get the JSON response:
result, err := ec2Svc.DescribeInstanceStatus(input)
where input is of type ec2.DescribeInstanceStatusInput
The following is the JSON response I get:
{
"InstanceStatuses": [
{
"AvailabilityZone": "ap-southeast-2b",
"Events": null,
"InstanceId": "[VALIDIMAGEID]",
"InstanceState": {
"Code": 16,
"Name": "running"
},
"InstanceStatus": {
"Details": [
{
"ImpairedSince": null,
"Name": "reachability",
"Status": "passed"
}
],
"Status": "ok"
},
"OutpostArn": null,
"SystemStatus": {
"Details": [
{
"ImpairedSince": null,
"Name": "reachability",
"Status": "passed"
}
],
"Status": "ok"
}
}
],
"NextToken": null
}
I then parse the result which is of type DescribeInstanceStatusOutput to String and then pass it to the function parseJson where I attempt to parse the JSON.
result, err := ec2Svc.DescribeInstanceStatus(input)
if err != nil {
fmt.Println("Error", err)
} else {
parseJson(result.String())
//fmt.Printf("%v\n", result)
}
func parseJson(ec2StatusDescription string){
//var x string = ec2StatusDescription.String()
//fmt.Print(ec2StatusDescription)
data := []byte(ec2StatusDescription)
var instanceOutputs InstanceOutput
json.Unmarshal(data, &instanceOutputs)
fmt.Print(instanceOutputs.InstanceStatuses[0].InstanceState.Name)
}
type InstanceOutput struct {
InstanceStatuses [] InstanceStatuses
NextToken *string
}
type InstanceStatuses struct {
AvailabilityZone string
Events *string
InstanceId string
InstanceState InstanceState
InstanceStatus InstanceStatus
OutpostArn *string
SystemStatus SystemStatus
}
type InstanceState struct {
Code int
Name string
}
type InstanceStatus struct {
Details [] InstanceDetails
Status string
}
type InstanceDetails struct {
ImpairedSince *string
Name string
Status string
}
type SystemStatus struct {
Details [] InstanceDetails
Status string
}
I am trying to print the instance state but I keep getting index out of range, and this is because the JSON is not being parsed properly. What am i missing here that's causing the json to not parse correctly? Or am I getting it completely wrong in what I'm doing here? Any help would be highly appreciated.
I'm trying to demarshal the JSON requests of Google Actions. These have arrays of tagged unions like this:
{
"requestId": "ff36a3cc-ec34-11e6-b1a0-64510650abcf",
"inputs": [{
"intent": "action.devices.QUERY",
"payload": {
"devices": [{
"id": "123",
"customData": {
"fooValue": 74,
"barValue": true,
"bazValue": "foo"
}
}, {
"id": "456",
"customData": {
"fooValue": 12,
"barValue": false,
"bazValue": "bar"
}
}]
}
}]
}
{
"requestId": "ff36a3cc-ec34-11e6-b1a0-64510650abcf",
"inputs": [{
"intent": "action.devices.EXECUTE",
"payload": {
"commands": [{
"devices": [{
"id": "123",
"customData": {
"fooValue": 74,
"barValue": true,
"bazValue": "sheepdip"
}
}, {
"id": "456",
"customData": {
"fooValue": 36,
"barValue": false,
"bazValue": "moarsheep"
}
}],
"execution": [{
"command": "action.devices.commands.OnOff",
"params": {
"on": true
}
}]
}]
}
}]
}
etc.
Obviously I can demarshal this to an interface{} and use fully dynamic type casts and everything to decode it, but Go has decent support for decoding to structs. Is there a way to do this elegantly in Go (like you can in Rust for example)?
I feel like you could almost do it by reading demarshalling to this initially:
type Request struct {
RequestId string
Inputs []struct {
Intent string
Payload interface{}
}
}
However once you have the Payload interface{} there doesn't seem to be any way to deserialise that into a struct (other than serialising it and deserialising it again which sucks. Is there any good solution?
Instead of unmarshaling Payload to an interface{} you can store it as a json.RawMessage and then unmarshal it based on the value of Intent. This is shown in the example in the json docs:
https://golang.org/pkg/encoding/json/#example_RawMessage_unmarshal
Using that example with your JSON and struct your code becomes something like this:
type Request struct {
RequestId string
Inputs []struct {
Intent string
Payload json.RawMessage
}
}
var request Request
err := json.Unmarshal(j, &request)
if err != nil {
log.Fatalln("error:", err)
}
for _, input := range request.Inputs {
var payload interface{}
switch input.Intent {
case "action.devices.EXECUTE":
payload = new(Execute)
case "action.devices.QUERY":
payload = new(Query)
}
err := json.Unmarshal(input.Payload, payload)
if err != nil {
log.Fatalln("error:", err)
}
// Do stuff with payload
}
I made https://github.com/byrnedo/pjson for exactly this reason.
So in your case you'd have:
type Input interface {
// Variant func is required
Variant() string
}
type ExecuteInput struct {
Payload struct {
// is any just to avoid typing it for this example
Commands []any `json:"commands"`
} `json:"payload"`
}
func (q ExecuteInput) Variant() string {
return "action.devices.EXECUTE"
}
type QueryInput struct {
Payload struct {
// is any just to avoid typing it for this example
Devices []any `json:"devices"`
} `json:"payload"`
}
func (q QueryInput) Variant() string {
return "action.devices.QUERY"
}
type Inputs []Input
func (i Inputs) MarshalJSON() ([]byte, error) {
return pjson.New(Inputs{}, pjson.WithVariantField("intent")).MarshalArray(i)
}
func (i *Inputs) UnmarshalJSON(bytes []byte) (err error) {
*i, err = pjson.New(Inputs{ExecuteInput{}, QueryInput{}}, pjson.WithVariantField("intent")).UnmarshalArray(bytes)
return
}
type Request struct {
RequestId string `json:"requestId"`
Inputs Inputs `json:"inputs"`
}
Try it on go playground
So I am trying to fetch the analytics of an app by pinging and endpoint. I make the GET request which is successfull (no errors there) but I am unable to decode the JSON
I need to to decode the following json into structs
{
"noResultSearches": {
"results": [
{
"count": 1,
"key": "\"note 9\""
},
{
"count": 1,
"key": "nokia"
}
]
},
"popularSearches": {
"results": [
{
"count": 4,
"key": "6"
},
{
"count": 2,
"key": "\"note 9\""
},
{
"count": 1,
"key": "nokia"
}
]
},
"searchVolume": {
"results": [
{
"count": 7,
"key": 1537401600000,
"key_as_string": "2018/09/20 00:00:00"
}
]
}
}
For which I am using the following structs
type analyticsResults struct {
Count int `json:"count"`
Key string `json:"key"`
}
type analyticsVolumeResults struct {
Count int `json:"count"`
Key int64 `json:"key"`
DateAsStr string `json:"key_as_string"`
}
type analyticsPopularSearches struct {
Results []analyticsResults `json:"results"`
}
type analyticsNoResultSearches struct {
Results []analyticsResults `json:"results"`
}
type analyticsSearchVolume struct {
Results []analyticsVolumeResults `json:"results"`
}
type overviewAnalyticsBody struct {
NoResultSearches analyticsNoResultSearches `json:"noResultSearches"`
PopularSearches analyticsPopularSearches `json:"popularSearches"`
SearchVolume analyticsSearchVolume `json:"searchVolume"`
}
I make a GET request to an endpoint and then use the response body to decode the json but I get an error. Following is a part of the code that stays in my ShowAnalytics function
func ShowAppAnalytics(app string) error {
spinner.StartText("Fetching app analytics")
defer spinner.Stop()
fmt.Println()
req, err := http.NewRequest("GET", "<some-endpoint>", nil)
if err != nil {
return err
}
resp, err := session.SendRequest(req)
if err != nil {
return err
}
spinner.Stop()
var res overviewAnalyticsBody
dec := json.NewDecoder(resp.Body)
err = dec.Decode(&res)
if err != nil {
return err
}
fmt.Println(res)
return nil
}
json: cannot unmarshal array into Go struct field
overviewAnalyticsBody.noResultSearches of type
app.analyticsNoResultSearches
What am I doing wrong here? Why do I get this error?
EDIT: After you edited, your current code works as-is. Check it out here: Go Playground.
Original answer follows.
There is some inconsistency between the code you posted and the error you get.
I tried it on the Go Playground (here's your version), and I get the following error:
json: cannot unmarshal number into Go struct field analyticsVolumeResults.key of type string
We get this error because in the JSON searchVolume.results.key is a number:
"key": 1537401600000,
And you used string in the Go model:
Key string `json:"key"`
If we change it to int64:
Key int64 `json:"key"`
It works, and prints (try it on the Go Playground):
{{[{1 "note 9"} {1 nokia}]} {[{4 6} {2 "note 9"} {1 nokia}]} {[{7 1537401600000 2018/09/20 00:00:00}]}}
If that key may sometimes be a number and sometimes a string, you may also use json.Number in the Go model:
Key json.Number `json:"key"`
type Status struct {
slug string `json:"slug"`
}
type Instance struct {
Slug string `json:"slug"`
Stat map[string]*Status `json:"status"`
}
This Json response is recieved for API call:
[ {
"status": {
"stop": false,
"traffic": true,
"label": null,
"dead": true,
"slug": "up",
},
"slug": "instances_raw",
"started_at": "15120736198",
"replacement": null
},
{
"status": {
"stop": false,
"traffic": true,
"label": null,
"dead": true,
"slug": "down",
},
"slug": "instance_raw2",
"started_at": "1512073194",
"replacement": null
}
]
I am trying to marshall json into above struct but running into issue:
instances := make([]Instance, 0)
res := api call return above json
body, _ := ioutil.ReadAll(res.Body)
json.Unmarshal(body, &instances)
fmt.Println("I am struct %s",instances)
It is marshalling into:
I am struct %s [{ map[stop:0xc42018e1b0 dead:0xc42018e1e0 label:<nil> running:0xc42018e220 down:0xc42018e150 traffic:0xc42018e180]}]
Can someone help me figure out why it is not marshalling as I am expecting?
Expected marshalling:
[{instances_raw map[slug:up]} {instances_raw2 map[slug:down]}]
The structs do not match the structure of the data. Perhaps you wanted this:
type Status struct {
Slug string `json:"slug"`
}
type Instance struct {
Slug string `json:"slug"`
Stat Status `json:"status"`
}
Output: [{instances_raw {up}} {instance_raw2 {down}}]
run it on the plaground
or this:
type Instance struct {
Slug string `json:"slug"`
Stat map[string]interface{} `json:"status"`
}
Output: [{instances_raw map[label: dead:true slug:up stop:false traffic:true]} {instance_raw2 map[slug:down stop:false traffic:true label: dead:true]}]
run it on the playground
Always check errors. The example JSON above is not valid and the json.Unmarshal function reports this error.