json.Unmarshal returning blank structure
Your struct fields are not exported. This is because they start with a lowercase letter.
EntryCount // <--- Exported
entryCount // <--- Not exported
When I say "not exported", I mean they are not visible outside of your package. Your package can happily access them because they are scoped locally to it.
As for the encoding/json
package though - it cannot see them. You need to make all of your fields visible to the encoding/json
package by making them all start with an uppercase letter, thereby exporting them:
type Status struct {
Status string
Node_id string
}
type Meta struct {
To string
From string
Id string
EntryCount int64
Size int64
Depricated bool
}
type Mydata struct {
Metadata Meta
Status []Status
}
See it working on the Go Playground here
You should also reference the Golang specification for answers. Specifically, the part that talks about Exported Identifiers.
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Kevin
Updated on September 14, 2022Comments
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Kevin about 1 year
I have a JSON blob that looks like this
{ "metadata":{ "id":"2377f625-619b-4e20-90af-9a6cbfb80040", "from":"2014-12-30T07:23:42.000Z", "to":"2015-01-14T05:11:51.000Z", "entryCount":801, "size":821472, "deprecated":false }, "status":[{ "node_id":"de713614-be3d-4c39-a3f8-1154957e46a6", "status":"PUBLISHED" }] }
and I have a little code to transform that back into go structs
type Status struct { status string node_id string } type Meta struct { to string from string id string entryCount int64 size int64 depricated bool } type Mydata struct { met meta stat []status } var realdata Mydata err1 := json.Unmarshal(data, &realdata) if err1 != nil { fmt.Println("error:", err1) } fmt.Printf("%T: %+v\n", realdata, realdata)
but what I see when I run this is just a zeroed structure
main.Mydata: {met:{to: from: id: entryCount:0 size:0 depricated:false} stat:[]}
I tried allocating the struct first but that also didn't work, I'm not sure why its not producing values, and its not returning an error
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sberry almost 9 yearsThis should not be downvoted, but you should mention the json tag values for giving the marshaled json a desired name. like
json:"entry_count"
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Simon Whitehead almost 9 yearsApologies. Fixed. I wrote this after heavy code discussions at work (where I am a .NET developer).
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sten over 6 yearsI'm going to upvote this because it helped me. But man does it make me cranky.