From 83381e49332a656f0c387ee0fd6a46117a7a5539 Mon Sep 17 00:00:00 2001
From: Lyle Mantooth <lyle@menteeth.us>
Date: Sat, 20 May 2023 11:50:57 -0400
Subject: [PATCH] Use MaxMindDb and thiserror.

---
 .gitignore |  1 +
 Cargo.toml |  4 +++-
 src/lib.rs | 27 +++++++++++++++++++++------
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/.gitignore b/.gitignore
index ea8c4bf..96ef6c0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /target
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
index 6a519ea..6f39e57 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,9 +1,11 @@
 [package]
 name = "locat"
-version = "0.2.0"
+version = "0.3.0"
 edition = "2021"
 publish = ["menteeth"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+maxminddb = "0.23"
+thiserror = "1"
diff --git a/src/lib.rs b/src/lib.rs
index d0f0d6a..e6c37a8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,17 +1,32 @@
 use std::net::IpAddr;
 
 /// Allows geo-locating IPs and keeps analytics.
-pub struct Locat {}
+pub struct Locat {
+    geoip: maxminddb::Reader<Vec<u8>>,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("maxminddb error: {0}")]
+    MaxMindDb(#[from] maxminddb::MaxMindDBError),
+}
 
 impl Locat {
-    pub fn new(_geoip_country_db_path: &str, _analytics_db_path: &str) -> Self {
-        // TODO: read geoip db, create analytics db
-        Self {}
+    pub fn new(geoip_country_db_path: &str, _analytics_db_path: &str) -> Result<Self, Error> {
+        // Todo: create analytics db.
+
+        Ok(Self {
+            geoip: maxminddb::Reader::open_readfile(geoip_country_db_path)?,
+        })
     }
 
     /// Converts an address to an ISO 3166-1 alpha-2 country code.
-    pub fn ip_to_iso_code(&self, _addr: IpAddr) -> Option<&str> {
-        None
+    pub fn ip_to_iso_code(&self, addr: IpAddr) -> Option<&str> {
+        self.geoip
+            .lookup::<maxminddb::geoip2::Country>(addr)
+            .ok()?
+            .country?
+            .iso_code
     }
 
     /// Returns a map of country codes to number of requests.