serde as used in Rocket

mongo_requests_a.rs

/**
   For a web server  objects are sent serialized into json, but a client
   could create an object from the http call response
**/
#[derive(Serialize, Deserialize, Debug, Clone)]
#[serde(crate = "rocket::serde")]
pub struct Restaurant {
    cuisine: String,
    borough: String,
    name: String,
    address: Address,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
#[serde(crate = "rocket::serde")]
pub struct Address {
    building: String,
    street: String,
    zipcode: String,
}

//  Convert Restaurant objects to an user friendly string
impl fmt::Display for Restaurant {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "place: {} cuisine: {} location: {}   {}", self.name, self.cuisine, self.borough, self.address)
    }
}

//  for serialization into JSON
impl Into<Document> for Restaurant {
    fn into(self) -> Document {
        doc!{ "name": self.name, "cuisine": self.cuisine, "borough": self.borough, "building": self.address.building, "street": self.address.street}
    }
}

impl fmt::Display for Address {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}  {}, {} ", self.building, self.street, self.zipcode)
    }
}