Here is a sample of my JSON post:
{
"jsonFilter" :[{
"column": "",
"contains": "",
"condition": "",
"not": true
}, {
"column": "",
"contains": "",
"condition": "",
"not": true
}]
}
My Echo framework handler:
func GetFilteredFileData(c echo.Context) error {
body := echo.Map{}
if err := c.Bind(&body); err != nil {
fmt.Println(err)
}
fmt.Println(body)
for key, element := range body {
fmt.Println(key, element)
}
}
Results:
jsonFilter [map[column:StartTimestamp condition:contains contains:<nil> not:false] map[column:SourceIP condition:startsWith contains:<nil> not:true]]
This is not index accessible, nor key accessible. I was told I needed to make a struct or 2, but all my efforts there did not work (gorilla schema, json.Marshal, etc)
What is the proper way to take this map and make it actually usable in a variable/struct ref?
You can unmarshal that json into the following struct:
type Body struct {
Filter []JSONFilter `json:"jsonFilter"`
}
type JSONFilter struct {
Column string `json:"column"`
Contains string `json:"contains"`
Condition string `json:"condition"`
Not bool `json:"not"`
}
I don't know about this echo framework, but it looks like something like this should work:
body := Body{}
if err := c.Bind(&body); err != nil {
fmt.Println(err)
}
Or, json.Unmarshal, if the above doesn't do.
Related
I want to serialize object of types.Project from github.com/compose-spec into JSON
However, a field of ths struct which is supposed to be array, is always serialized into map.
package main
import (
"encoding/json"
types "github.com/compose-spec/compose-go/types"
)
func main() {
out := types.Project{
Name: "foo",
Services: []types.ServiceConfig{ // <- notice this field is an array
{
Name: "bar",
Image: "hello-world",
},
},
}
buf, err := json.Marshal(out)
if err != nil {
panic(err)
}
println(string(buf)) // <- notice the Services field now a map, which is incorrect!
var in types.Project
if err := json.Unmarshal(buf, &in); err != nil {
panic(err)
}
}
The code fails to run:
{"name":"foo","services":{"bar":{"command":null,"entrypoint":null,"image":"hello-world"}}}
panic: json: cannot unmarshal object into Go struct field Project.services of type types.Services
goroutine 1 [running]:
main.main()
/tmp/sandbox1081064727/prog.go:29 +0x168
The out object is serialized as
{
"name": "foo",
"services": {
"bar": {
"command": null,
"entrypoint": null,
"image": "hello-world"
}
}
}
which should really be something like
{
"name": "foo",
"services": [
{
"name": "bar",
"command": null,
"entrypoint": null,
"image": "hello-world"
}
]
}
The behavior you're seeing is correct with respect to the compose file specification, which says:
A Compose file MUST declare a services root element as a map whose keys are string representations of service names, and whose values are service definitions.
The transformation of the list to a map is implemented by the custom marshalers in compose-go/types.go:
// MarshalYAML makes Services implement yaml.Marshaller
func (s Services) MarshalYAML() (interface{}, error) {
services := map[string]ServiceConfig{}
for _, service := range s {
services[service.Name] = service
}
return services, nil
}
// MarshalJSON makes Services implement json.Marshaler
func (s Services) MarshalJSON() ([]byte, error) {
data, err := s.MarshalYAML()
if err != nil {
return nil, err
}
return json.MarshalIndent(data, "", " ")
}
I would like to reqeive a JSON response withing a client application and unmarshal this response into a struct. To ensure that the struct stays the same accross all client apps using this package, I would like to define the JSON responses as protobuf messages. I am having difficulties unmarshaling the JSON to the protobuf generated structs.
I have the following JSON data:
[
{
"name": "C1",
"type": "docker"
},
{
"name": "C2",
"type": "docker"
}
]
I have modeled my protobuf definitions like this:
syntax = "proto3";
package main;
message Container {
string name = 1;
string type = 2;
}
message Containers {
repeated Container containers = 1;
}
Using this pattern with structs normaly works, but for some reason using these proto definitions causes issues. The below code demonstrates a working and a non-working example. Although one of the versions work, I am unable to use this solution, since []*Container does not satisfy the proto.Message interface.
package main
import (
"encoding/json"
"fmt"
"strings"
"github.com/gogo/protobuf/jsonpb"
)
func working(data string) ([]*Container, error) {
var cs []*Container
return cs, json.Unmarshal([]byte(data), &cs)
}
func notWorking(data string) (*Containers, error) {
c := &Containers{}
jsm := jsonpb.Unmarshaler{}
if err := jsm.Unmarshal(strings.NewReader(data), c); err != nil {
return nil, err
}
return c, nil
}
func main() {
data := `
[
{
"name": "C1",
"type": "docker"
},
{
"name": "C2",
"type": "docker"
}
]`
w, err := working(data)
if err != nil {
panic(err)
}
fmt.Print(w)
nw, err := notWorking(data)
if err != nil {
panic(err)
}
fmt.Print(nw.Containers)
}
Running this gives the following output:
[name:"C1" type:"docker" name:"C2" type:"docker" ]
panic: json: cannot unmarshal array into Go value of type map[string]json.RawMessage
goroutine 1 [running]:
main.main()
/Users/example/go/src/github.com/example/example/main.go:46 +0x1ee
Process finished with exit code 2
Is there a way to unmarshal this JSON to Containers? Or alternatively, make []*Container to satisfy the proto.Message interface?
For the message Containers, i.e.
message Containers {
repeated Container containers = 1;
}
The correct JSON should look like:
{
"containers" : [
{
"name": "C1",
"type": "docker"
},
{
"name": "C2",
"type": "docker"
}
]
}
If you cannot change the JSON then you can utilize the func that you've created
func working(data string) ([]*Container, error) {
var cs []*Container
err := json.Unmarshal([]byte(data), &cs)
// handle the error here
return &Containers{
containers: cs,
}, nil
}
You should use NewDecoder to transfer the data to jsonDecoder and then traverse
the array.The code is this
func main() {
data := `
[
{
"name": "C1",
"type": "docker"
},
{
"name": "C2",
"type": "docker"
}
]`
jsonDecoder := json.NewDecoder(strings.NewReader(data))
_, err := jsonDecoder.Token()
if err != nil {
log.Fatal(err)
}
var protoMessages []*pb.Container
for jsonDecoder.More() {
protoMessage := pb.Container{}
err := jsonpb.UnmarshalNext(jsonDecoder, &protoMessage)
if err != nil {
log.Fatal(err)
}
protoMessages = append(protoMessages, &protoMessage)
}
fmt.Println("%s", protoMessages)
}
I'm trying to import a large JSON document from a file, empty all arrays matching a specific key or pattern, then output it, without having to marshall the entire document.
It will be run as part of a periodic batch job, so performance/efficiency is not a priority.
Simplicity, and making sure the code is agnostic to the overall JSON structure, is more important.
Is there an easy way to do solve this in Go?
Example input:
{
"panels": [
{
"alert": {
"executionErrorState": "alerting",
"notifications": [
{
"uid": "fRLbH_6Zk"
},
{
"uid": "8gamKl6Waz"
}
]
}
},
{
"alert": {
"executionErrorState": "alerting",
"notifications": [
{
"uid": "DqjrD_6Zk"
}
]
}
}
]
}
Desired output (all entries in 'alert.notifications' in 'panels' removed):
{
"panels": [
{
"alert": {
"executionErrorState": "alerting",
"notifications": []
}
},
{
"alert": {
"executionErrorState": "alerting",
"notifications": []
}
}
]
}
you can use read streams, to read objects one by one. Code will be unmarshall first object, but will have error on the next one. Its like approve of state that code dont read whole file, here example:
package main
import (
"encoding/json"
"fmt"
"log"
"strings"
)
func main() {
const jsonStream = `
[
{"Name": "Ed", "Text": "Knock knock."},
asdasd sadasd,
`
type Message struct {
Name, Text string
}
dec := json.NewDecoder(strings.NewReader(jsonStream))
// read open bracket
t, err := dec.Token()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%T: %v\n", t, t)
// while the array contains values
for dec.More() {
var m Message
// decode an array value (Message)
err := dec.Decode(&m)
if err != nil {
log.Fatal(err)
}
fmt.Printf("%v: %v\n", m.Name, m.Text)
}
// read closing bracket
t, err = dec.Token()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%T: %v\n", t, t)
}
I'm trying to check if a Json string matches an Avro schema. I don't care about doing serialization of the data, just getting a bool result of isValidJson=true/false.
I'll go with every golang library.
I've tried to write something with this goavro lib, but it didn't work for me, maybe because I'm new to golang.
Desired pseudo code:
func main() {
avroSchema :=
`{"type":"record","name":"raw","namespace":"events","fields":[{"name":"my_int","type":["null","int"],"default":null},{"name":"my_string","type":["null","string"],"default":"null"},{"name":"my_string2","type":null}]}`
jsonString := `{"my_int": 3, "my_string": "foo", "my_string2": null}`
ok ;= isValidJson(jsonString, avroSchema)
}
Any idea how to implement the isValidJson(..) method?
Your schema json is invalid, it's missing the terminating }, so goavro.NewCodec returns an error.
Then your json string definitely doesn't match the schema, the json values must be a {type: value}.
You can use the following corrected schema and example string to validate it.
func main() {
avroSchema := `
{
"type":"record",
"name":"raw",
"namespace":"events",
"fields":[
{
"name":"my_int",
"type":[
"null",
"int"
],
"default":null
},
{
"name":"my_string",
"type":[
"null",
"string"
],
"default":null
},
{
"name":"my_string2",
"type":"null"
}
]
}`
codec, err := goavro.NewCodec(avroSchema)
if err != nil {
log.Fatalf("Codec error: %v", err)
}
jsonString := `{"my_int": {"int":3}, "my_string": {"string":"foo"}, "my_string2": null}`
decoded, _, err := codec.NativeFromTextual([]byte(jsonString))
if err != nil {
log.Fatalf("NativeFromTextual error: %v", err)
}
log.Println("Decoded:", decoded)
}
This prints:
Decoded: map[my_int:map[int:3] my_string:map[string:foo]
my_string2:]
I have a solr response in JSON format which looks like this:
{
"responseHeader": {
"status": 0,
"QTime": 0,
"params": {
"q": "solo",
"wt": "json"
}
},
"response": {
"numFound": 2,
"start": 0,
"docs": [
{
<Large nested JSON element>
},
{
<Large nested JSON element>
}
]
}
}
Now, in my Golang app, I would like to quickly remove the "responseHeader" so that I can return the "response" alone. How can I do this without creating large structures?
Edit 1
The answer by evanmcdonnal was the solution to this problem, but it had some minor typos, this is what I ended up using:
var temp map[string]interface{}
if err := json.Unmarshal(body, &temp); err != nil {
panic(err.Error())
}
result, err := json.Marshal(temp["response"])
Here's a really brief example of how to do this quickly and easily. The steps are; unmarshal into the universal map[string]interface{} then, assuming no errors, marshal only the inner object which you want.
var temp := &map[string]interface{}
if err := json.Unmarshal(input, temp); err != nil {
return err;
}
return json.Marshal(temp["response"])
I wrote a package µjson to do exactly that: performing generic transformations on JSON documents without unmarshalling them.
Run on Go Playground
input := []byte(`
{
"responseHeader": {
"status": 0,
"QTime": 0,
"params": {
"q": "solo",
"wt": "json"
}
},
"response": {
"numFound": 2,
"start": 0,
"docs": [
{ "name": "foo" },
{ "name": "bar" }
]
}
}`)
blacklistFields := [][]byte{
[]byte(`"responseHeader"`), // note the quotes
}
b := make([]byte, 0, 1024)
err := ujson.Walk(input, func(_ int, key, value []byte) bool {
for _, blacklist := range blacklistFields {
if bytes.Equal(key, blacklist) {
// remove the key and value from the output
return false
}
}
// write to output
if len(b) != 0 && ujson.ShouldAddComma(value, b[len(b)-1]) {
b = append(b, ',')
}
if len(key) > 0 {
b = append(b, key...)
b = append(b, ':')
}
b = append(b, value...)
return true
})
if err != nil {
panic(err)
}
fmt.Printf("%s", b)
// Output: {"response":{"numFound":2,"start":0,"docs":[{"name":"foo"},{"name":"bar"}]}}
You can read more about it on the blog post. I put the answer here just in case someone else might need it.