Add PYAPP_DISTRIBUTION_PATH_PREFIX option (#132)

Cargo.toml

@@ -49,6 +49,7 @@ passthrough = [
   "PYAPP_DISTRIBUTION_EMBED",
   "PYAPP_DISTRIBUTION_FORMAT",
   "PYAPP_DISTRIBUTION_PATH",
+  "PYAPP_DISTRIBUTION_PATH_PREFIX",
   "PYAPP_DISTRIBUTION_PIP_AVAILABLE",
   "PYAPP_DISTRIBUTION_PYTHON_PATH",
   "PYAPP_DISTRIBUTION_SITE_PACKAGES_PATH",

build.rs

@@ -263,6 +263,23 @@ fn normalize_project_name(name: &String) -> String {
         .to_lowercase()
 }
 
+fn normalize_relative_path(path: &String) -> String {
+    if env::var("CARGO_CFG_TARGET_OS").unwrap() == "windows" {
+        path.replace('/', "\\")
+            .strip_prefix('\\')
+            .unwrap_or(path)
+            .strip_suffix('\\')
+            .unwrap_or(path)
+            .to_string()
+    } else {
+        path.strip_prefix('/')
+            .unwrap_or(path)
+            .strip_suffix('/')
+            .unwrap_or(path)
+            .to_string()
+    }
+}
+
 fn embed_file(name: &str) -> PathBuf {
     [
         env::var("CARGO_MANIFEST_DIR").unwrap().as_str(),
@@ -572,8 +589,8 @@ fn set_python_path(distribution_source: &str) {
     let distribution_variable = "PYAPP_DISTRIBUTION_PYTHON_PATH";
     let on_windows = env::var("CARGO_CFG_TARGET_OS").unwrap() == "windows";
     let python_path = env::var(distribution_variable).unwrap_or_default();
-    let relative_path = if !python_path.is_empty() {
-        python_path
+    let mut relative_path = if !python_path.is_empty() {
+        normalize_relative_path(&python_path)
     } else if !env::var("PYAPP_DISTRIBUTION_PATH")
         .unwrap_or_default()
         .is_empty()
@@ -608,6 +625,11 @@ fn set_python_path(distribution_source: &str) {
     } else {
         "bin/python3".to_string()
     };
+
+    let path_prefix = env::var("PYAPP_DISTRIBUTION_PATH_PREFIX").unwrap_or_default();
+    if !path_prefix.is_empty() {
+        relative_path = normalize_relative_path(&path_prefix);
+    }
     set_runtime_variable(distribution_variable, &relative_path);
 
     let installation_variable = "PYAPP__INSTALLATION_PYTHON_PATH";
@@ -625,8 +647,8 @@ fn set_site_packages_path(distribution_source: &str) {
     let on_windows = env::var("CARGO_CFG_TARGET_OS").unwrap() == "windows";
     let python_version = get_python_version();
     let site_packages_path = env::var(distribution_variable).unwrap_or_default();
-    let relative_path = if !site_packages_path.is_empty() {
-        site_packages_path
+    let mut relative_path = if !site_packages_path.is_empty() {
+        normalize_relative_path(&site_packages_path)
     } else if distribution_source.starts_with(DEFAULT_CPYTHON_SOURCE) {
         if python_version == "3.7" {
             if on_windows {
@@ -662,6 +684,11 @@ fn set_site_packages_path(distribution_source: &str) {
     } else {
         format!("lib/python{}/site-packages", python_version)
     };
+
+    let path_prefix = env::var("PYAPP_DISTRIBUTION_PATH_PREFIX").unwrap_or_default();
+    if !path_prefix.is_empty() {
+        relative_path = normalize_relative_path(&path_prefix);
+    }
     set_runtime_variable(distribution_variable, &relative_path);
 
     let installation_variable = "PYAPP__INSTALLATION_SITE_PACKAGES_PATH";

docs/changelog.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ***Added:***
 
+- Add `PYAPP_DISTRIBUTION_PATH_PREFIX` option for easier configuring of custom distribution internal paths
 - Add `PYAPP_ALLOW_UPDATES` option for enabling the `update` management command when project installation is skipped
 
 ***Fixed:***

docs/config/distribution.md

@@ -60,6 +60,10 @@ You may set the relative path to the Python executable after unpacking the archi
 
 You may set the relative path to the [`site-packages`](https://docs.python.org/3/library/site.html) directory after unpacking the archive with the `PYAPP_DISTRIBUTION_SITE_PACKAGES_PATH` option. The default is `Lib\site-packages` on Windows and `lib/python<ID>/site-packages` on all other platforms where `<ID>` is the defined [distribution ID](#known).
 
+### Path prefix
+
+If the [Python executable](#python-location) and the [`site-packages` directory](#site-packages-location) are at the default locations but nested under top-level directories, you may set the `PYAPP_DISTRIBUTION_PATH_PREFIX` option to the common prefix of the two paths to avoid having to manually set those options.
+
 ### pip availability
 
 You may indicate whether pip is already installed by setting the `PYAPP_DISTRIBUTION_PIP_AVAILABLE` option to `true` or `1`. This elides the check for installation when [upgraded virtual environments](installation.md#virtual-environments) are enabled.