Get OAuth secret and token from XDG data directory

Stop using the `google-calendar3` directory and secret file and use an
application-specific one.

3 files changed, 29 insertions, 21 deletions

diff --git a/Cargo.lock b/Cargo.lock
index b222a17..800acc1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -261,13 +261,13 @@ dependencies = [
  "chrono",
  "exitcode",
  "google-calendar3",
- "home",
  "hyper",
  "hyper-rustls",
  "mailparse",
  "regex",
  "serde_json",
  "tokio",
+ "xdg",
  "yup-oauth2",
 ]
 
@@ -323,15 +323,6 @@ dependencies = [
 ]
 
 [[package]]
-name = "home"
-version = "0.5.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2456aef2e6b6a9784192ae780c0f15bc57df0e918585282325e8c8ac27737654"
-dependencies = [
- "winapi",
-]
-
-[[package]]
 name = "http"
 version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1128,6 +1119,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
 [[package]]
+name = "xdg"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d089681aa106a86fade1b0128fb5daf07d5867a509ab036d99988dec80429a57"
+
+[[package]]
 name = "yup-oauth2"
 version = "5.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index 6e17021..f63a736 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,11 +9,11 @@ base64 = "0.13.0"
 chrono = "0.4.19"
 exitcode = "1.1.2"
 google-calendar3 = "2.0.4+20210327"
-home = "0.5.3"
 hyper = "0.14.7"
 hyper-rustls = "0.22.1"
 mailparse = "0.13.4"
 regex = "1.5.4"
 serde_json = "1.0.64"
 tokio = { version = "1.6.0", features = ["rt-multi-thread"] }
+xdg = "2.2.0"
 yup-oauth2 = "5.1.0"
diff --git a/src/main.rs b/src/main.rs
index fb5853c..f8b7d26 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,20 +1,21 @@
-use anyhow;
+use anyhow::{self, Context};
 use base64;
 use chrono::DateTime;
 use google_calendar3::api::{Event, EventAttendee};
 use google_calendar3::CalendarHub;
-use home;
 use hyper;
 use hyper_rustls;
 use mailparse;
 use regex::Regex;
 use tokio;
+use xdg;
 use yup_oauth2 as oauth2;
 
 use std::env;
 use std::fmt;
 use std::fs;
 use std::io::{self, Read};
+use std::path::{Path, PathBuf};
 use std::process;
 use std::str;
 
@@ -154,11 +155,7 @@ async fn rsvp(event_id: &str, response: &EventResponseStatus) -> anyhow::Result<
         secret,
         oauth2::InstalledFlowReturnMethod::HTTPRedirect,
     )
-        .persist_tokens_to_disk(
-            home::home_dir()
-                .ok_or(anyhow::anyhow!("error getting home directory"))?
-                .join(".google-service-cli/google-calendar-rsvp")
-        )
+        .persist_tokens_to_disk(local_data_file("token.json")?)
         .build()
         .await?;
 
@@ -202,9 +199,14 @@ async fn rsvp(event_id: &str, response: &EventResponseStatus) -> anyhow::Result<
 
 fn secret_from_file() -> anyhow::Result<oauth2::ApplicationSecret> {
     let f = fs::File::open(
-        home::home_dir()
-            .ok_or(anyhow::anyhow!("error getting home directory"))?
-            .join(".google-service-cli/calendar3-secret.json"),
+        local_data_file("oauth-secret.json")
+            .context(format!(
+                "Missing OAuth2 secret file. Create an application on the Google Developer Console (https://console.developers.google.com/) and download the JSON secret file to '{}'.",
+                xdg::BaseDirectories::with_prefix("google-calendar-rsvp")?
+                    .get_data_home()
+                    .join("oauth-secret.json")
+                    .display()
+            ))?,
     )?;
 
     let console_secret: oauth2::ConsoleApplicationSecret = serde_json::from_reader(f)?;
@@ -213,6 +215,15 @@ fn secret_from_file() -> anyhow::Result<oauth2::ApplicationSecret> {
         .ok_or(anyhow::anyhow!("OAuth2 application secret not found"))
 }
 
+fn local_data_file<P: AsRef<Path>>(file: P) -> anyhow::Result<PathBuf> {
+    let xdg_dirs = xdg::BaseDirectories::with_prefix("google-calendar-rsvp")?;
+
+    Ok(
+        xdg_dirs.find_data_file(&file)
+            .ok_or(anyhow::anyhow!("error getting XDG data path"))?
+    )
+}
+
 fn event_id_from_base64(event_id: &str) -> anyhow::Result<String> {
     let decoded = match base64::decode(event_id) {
         Ok(d) => d,