Go not interpreting http request correctly - mongodb

Question

I have a mongoDb instance connected and my request (from my React app) gets a 200 back. I can see the collection in Mondodb as "cats" with a record for each cat but the cat records looks like:
_id:5f66641bad25efa40b810d83 - fine
name:"" - should not be blank
favorite:false -should be true
I had had some cors problems at first so I changed what was "Content-Type" to "content-type" (for Access-Control-Allow-Headers) and that "fixed" the cors issue. I have no idea if that is what is breaking the code though.
Since this is my first time setting up a database on my own I am just not sure where I have broken the code. Any help would be appreciated.
Here is my CreateCat method:
func CreateCat(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Context-Type", "application/json; charset=utf-8")
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Header().Set("Access-Control-Allow-Methods", "POST")
w.Header().Set("Access-Control-Allow-Headers", "content-type")
var cat models.Cat
_ = json.NewDecoder(r.Body).Decode(&cat)
fmt.Println(cat)
insertOneFavoriteCat(cat)
json.NewEncoder(w).Encode(cat)
}
Here is my model:
type Cat struct {
ID primitive.ObjectID `json:"_id,omitempty" bson:"_id,omitempty"`
Name string `json:"name,string"`
Favorite bool `json:"favorite,string"`
}
This is what println prints: { false}
and if you are curious if it's my frontend, this is the request getting sent:
{"cat":{"name":"tabby","favorite":true}}

Answer 1

Problem is that JSON MongoDB returns doesn't match how your struct would be decoded. That false comes from Favorite field which cannot be found in JSON object with cat key returned by MongoDB. To decode this type of response you need to define a wrapping struct (as CatModel in my example below) because your Cat is not top level object but just a member key of upper level JSON object:
type CatModel struct {
Cat struct {
ID primitive.ObjectID `json:"_id,omitempty" bson:"_id,omitempty"`
Name string `json:"name"`
Favorite bool `json:"favorite"`
} `json:"cat"`
}
Also you have typo (Context-Type instead of Content-Type) in header name. Correct Header().Set() is:
w.Header().Set("Content-Type", "application/json; charset=utf-8")