Add a configurable base URL.

.env.example

@@ -3,3 +3,6 @@
 
 # The User-Agent string for HTTP requests, replace the email with yours.
 # USER_AGENT="Tildes Statistics (your-email@example.org)"
+
+# A different base URL than the default "https://tildes.net".
+# BASE_URL="https://example.org"

source/snapshots/create.rs

@@ -10,12 +10,13 @@ use {
 use crate::{
   group_data::{GroupDataActiveModel, GroupDataEntity},
   snapshots::{SnapshotActiveModel, SnapshotModel},
-  utilities::{create_http_client, download_html, today},
+  utilities::{create_http_client, download_html, get_base_url, today},
 };
 
 impl SnapshotModel {
   /// Create a snapshot for today.
   pub async fn create(db: &DatabaseConnection, force: bool) -> Result<()> {
+    let base_url = get_base_url();
     let snapshot_date = today();
     match (force, Self::get_by_date(db, snapshot_date).await?) {
       (true, Some(existing)) => {
@@ -44,7 +45,7 @@ impl SnapshotModel {
 
     let http = create_http_client()?;
     let group_list = GroupList::from_html(
-      &download_html(&http, "https://tildes.net/groups").await?,
+      &download_html(&http, format!("{}/groups", base_url)).await?,
     )?;
 
     let mut groups_to_insert = vec![];
@@ -52,8 +53,7 @@ impl SnapshotModel {
     for summary in group_list.summaries {
       debug!(summary = ?summary);
       let group = Group::from_html(
-        &download_html(&http, format!("https://tildes.net/{}", summary.name))
-          .await?,
+        &download_html(&http, format!("{}/{}", base_url, summary.name)).await?,
       )?;
 
       debug!(group = ?group);

source/templates/index.html

@@ -34,7 +34,7 @@
       {% for group in groups %}
       <tr>
         <td>
-          <a href="https://tildes.net/{{ group.name }}">{{ group.name }}</a>
+          <a href="{{ base_url }}/{{ group.name }}">{{ group.name }}</a>
         </td>
         <td>{{ group.subscribers }}</td>
         <td>
@@ -62,7 +62,7 @@
   </p>
 
   <p class="bold">
-    Consider joining <a href="https://tildes.net">Tildes</a>, a non-profit
+    Consider joining <a href="{{ base_url }}">Tildes</a>, a non-profit
     community site driven by its users' interests.
   </p>
 </footer>

source/templates/mod.rs

@@ -10,12 +10,18 @@ use {
   color_eyre::Result,
 };
 
-use crate::{group_data::GroupDataModel, utilities::today};
+use crate::{
+  group_data::GroupDataModel,
+  utilities::{get_base_url, today},
+};
 
 /// The template for the home page.
 #[derive(Template)]
 #[template(path = "index.html")]
 pub struct HomeTemplate {
+  /// The base URL for links to the Tildes instance.
+  pub base_url: String,
+
   /// Extra HTML to insert in the body.
   pub extra_body_html: String,
 
@@ -45,6 +51,7 @@ impl HomeTemplate {
     let extra_head_html = read_to_string("extra-head.html").await;
 
     Self {
+      base_url: get_base_url(),
       extra_body_html: extra_body_html.unwrap_or_default(),
       extra_head_html: extra_head_html.unwrap_or_default(),
       groups,

source/utilities.rs

@@ -52,6 +52,12 @@ pub async fn download_html(
   Ok(Html::parse_document(&html))
 }
 
+/// Get the `BASE_URL` environment variable or the default `https://tildes.net`
+/// base URL.
+pub fn get_base_url() -> String {
+  get_env_var("BASE_URL").unwrap_or_else(|_| "https://tildes.net".to_string())
+}
+
 /// Shorthand for [`std::env::var`] with wrapped error message.
 pub fn get_env_var(key: &str) -> Result<String> {
   std::env::var(key).wrap_err(key.to_string())