Appending JSON struct to JSON file Golang
To achieve your output, define struct as follows-
type Identification struct {
ID string
Phone int64
Email string
}
And perform operation as follows-
// define slice of Identification
var idents []Identification
// Unmarshall it
err := json.Unmarshal([]byte(jsonText), &idents)
// add further value into it
idents = append(idents, Identification{ID: "ID", Phone: 15555555555, Email: "Email"})
// now Marshal it
result, error := json.Marshal(idents)
// now result has your targeted JSON structure
Sample program of above explanation https://play.golang.org/p/67dqOaCWHI
Rohit Panikar
Updated on June 18, 2022Comments
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Rohit Panikar almost 2 years
I have a JSON document of Users where they have an ID#, Phone#, and Email. Upon input of another ID, Phone, and Email, I want to take a new user's information and append it to the file. I have a structure that only contains an {ID: #, Phone: #, Email: #} and that's working fine. But my JSON file becomes as such:
[{"ID":"ABCD","Phone":1234567890,"Email":"[email protected]"}] [{"ID":"EFGH","Phone":1234567890,"Email":"[email protected]"}] [{"ID":"IJKL","Phone":1234567890,"Email":"[email protected]"}] [{"ID":"MNOP","Phone":1234567890,"Email":"[email protected]"}] [{"ID":"QRST","Phone":1234567890,"Email":"[email protected]"}] [{"ID":"UVWX","Phone":1234567890,"Email":"[email protected]"}]
So I'm able to append to the document, but it's a new JSON structure enclosed by brackets []. Below is my code. I omitted the actual hashed ID.
func ToIds(e string, p int64) { hashed := GenId() var jsonText = []byte(`[ {"ID": "", "Phone": 0, "Email": ""} ]`) var I Identification err := json.Unmarshal([]byte(jsonText), &I) if err != nil { fmt.Println(err) } I[0].ID = hashed I[0].Phone = p I[0].Email = e result, error := json.Marshal(I) if error != nil { fmt.Println(error) } f, erro := os.OpenFile("FILE_PATH", os.O_APPEND|os.O_WRONLY, 0666) if erro != nil { fmt.Println(erro) } n, err := io.WriteString(f, string(result)) if err != nil { fmt.Println(n, err) } }
This may be of use, here is my Identification struct.
type Identification []struct { ID string Phone int64
Email string }Essentially, I want the outside brackets, and inside those brackets I want to append multiple users. Something like this:
[ {"id":"A", "phone":17145555555, "email":"[email protected]"}, {"id":"B","phone":15555555555,"email":"[email protected]"}, {"id":"C","phone":14155555555,"email":"[email protected]"}, {"id":"D","phone":17135555555,"email":"[email protected]"}, {"id":"E","phone":17125555555,"email":"[email protected]"}, {"id":"F","phone":17125555555,"email":"[email protected]"}, {"id":"G","phone":14055555555,"email":"[email protected]"}, {"id":"H","phone":13105555555,"email":"[email protected]"} ]
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Rohit Panikar almost 7 yearsThe only reason I defined my struct in my manner was so that I could iterate through it by saying: for index := range Identification. How could I iterate through your structure? The reason for iteration is to make sure I'm not duplicating the user.
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jeevatkm almost 7 yearsYou can iterate
idents
value. -
Rohit Panikar almost 7 yearsI'm sorry, what do you mean by iterating through "idents value"?
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jeevatkm almost 7 yearsRefer to the play.golang link in the answer added iteration too.
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Rohit Panikar almost 7 yearsAppreciate the help.