sqlpage.environment_variable('inexistant') = null

fixes #746

Author: lovasoa

CHANGELOG.md

@@ -30,6 +30,7 @@
 - Temporarily disable automatic tick amount calculation in the chart component. This was causing issues with mislabeled x-axis data, because of a bug in ApexCharts.
 - Add a new `max_recursion_depth` configuration option to limit the depth of recursion allowed in the `run_sql` function.
 - Fix a bug where the results of the `JSON` function in sqlite would be interpreted as a string instead of a json object.
+- Fix a bug where the `sqlpage.environment_variable` function would return an error if the environment variable was not set. Now it returns `null` instead.
 
 ## 0.31.0 (2024-11-24)
 

src/webserver/database/sqlpage_functions/functions.rs

@@ -89,10 +89,13 @@ async fn current_working_directory() -> anyhow::Result<String> {
 }
 
 /// Returns the value of an environment variable.
-async fn environment_variable(name: Cow<'_, str>) -> anyhow::Result<Cow<'_, str>> {
-    std::env::var(&*name)
-        .with_context(|| format!("unable to access the environment variable {name}"))
-        .map(Cow::Owned)
+async fn environment_variable(name: Cow<'_, str>) -> anyhow::Result<Option<Cow<'_, str>>> {
+    match std::env::var(&*name) {
+        Ok(value) => Ok(Some(Cow::Owned(value))),
+        Err(std::env::VarError::NotPresent) if name.contains("=") || name.contains("\0") => anyhow::bail!("Invalid environment variable name: {name:?}. Environment variable names cannot contain an equals sign or a null character."),
+        Err(std::env::VarError::NotPresent) => Ok(None),
+        Err(err) => Err(err).with_context(|| format!("unable to read the environment variable {name:?}"))
+    }
 }
 
 /// Executes an external command and returns its output.

tests/sql_test_files/it_works_env_var_empty.sql

@@ -0,0 +1 @@
+select 'text' as component, coalesce(sqlpage.environment_variable('I_DO_NOT_EXIST'), 'It works !') as contents;