maxminddb-rust, get value of country for certain language - rust

Question

I decided to start learning Rust, I haven't finished their book yet but I am trying to build and run other projects so I can learn from the source code. I am now interested in maxmind-rust crate and specifically I want to retrieve country, city and asn values from the .mmdb file.
I tried to convert struct maxmind::geoip2::Country to string and use json crate but resulted in errors that I couldn't fix myself.
The code used:
use maxminddb::geoip2;
use std::net::IpAddr;
use std::str::FromStr;
fn main()
{
let mmdb_file = maxminddb::Reader::open("C:\\path\\to\\GeoLite2-City.mmdb").unwrap();
let ip_addr: IpAddr = FromStr::from_str("8.8.8.8").unwrap();
let geoip2_country: geoip2::Country = mmdb_file.lookup(ip_addr).unwrap();
println!("{:?}", geoip2_country);
}
The output is:
Country
{
continent: Some(Continent
{
code: Some("NA"),
geoname_id: Some(6255149),
names: Some(
{
"de": "Nordamerika",
"en": "North America",
"es": "Norteam?rica",
"fr": "Am?rique du Nord",
"ja": "?????",
"pt-BR": "Am?rica do Norte",
"ru": "???????? ???????",
"zh-CN": "???"
})
}),
country: Some(Country
{
geoname_id: Some(6252001),
iso_code: Some("US"),
names: Some(
{
"de": "USA",
"en": "United States",
"es": "Estados Unidos",
"fr": "?tats-Unis",
"ja": "???????",
"pt-BR": "Estados Unidos",
"ru": "???",
"zh-CN": "??"
})
}),
registered_country: Some(Country
{
geoname_id: Some(6252001),
iso_code: Some("US"),
names: Some(
{
"de": "USA",
"en": "United States",
"es": "Estados Unidos",
"fr": "?tats-Unis",
"ja": "???????",
"pt-BR": "Estados Unidos",
"ru": "???",
"zh-CN": "??"
})
}),
represented_country: None,
traits: None
}
which is the maxminddb::geoip2::Country struct (http://oschwald.github.io/maxminddb-rust/maxminddb/geoip2/struct.Country.html)
Changing the last line of code to
println!("{:?}", geoip2_country.country);
outputs only the country field:
country: Some(Country
{
geoname_id: Some(6252001),
iso_code: Some("US"),
names: Some(
{
"de": "USA",
"en": "United States",
"es": "Estados Unidos",
"fr": "?tats-Unis",
"ja": "???????",
"pt-BR": "Estados Unidos",
"ru": "???",
"zh-CN": "??"
})
}),
But looking at the structure of maxminddb::geoip2::model::Country (http://oschwald.github.io/maxminddb-rust/maxminddb/geoip2/model/struct.Country.html), I am very confused as to how I can retrieve from this struct and its pair (language_code, country_name) if I wanted to get the name of country for "en" key.

Answer 1

You could have a look at how the tests are written and it will give you some idea how to extract the information you are looking for:
https://github.com/oschwald/maxminddb-rust/blob/master/src/maxminddb/reader_test.rs
(actually, after looking at the tests I didn't find any example extracting what you are looking for)
That should return what you expect:
let country_name = geoip2_country.country
.and_then(|cy| cy.names)
.and_then(|n| n.get("en")
.map(String::from));