Add CLI export-settings command

2 files changed, 57 insertions, 5 deletions

diff --git a/mullvad-cli/src/cmds/patch.rs b/mullvad-cli/src/cmds/patch.rs
index d5a79aaef9..c935c08aac 100644
--- a/mullvad-cli/src/cmds/patch.rs
+++ b/mullvad-cli/src/cmds/patch.rs
@@ -2,15 +2,15 @@ use anyhow::{anyhow, Context, Result};
 use mullvad_management_interface::MullvadProxyClient;
 use std::{
     fs::File,
-    io::{stdin, BufRead, BufReader},
+    io::{stdin, stdout, BufRead, BufReader, BufWriter, Write},
     path::Path,
 };
 
 /// Maximum size of a settings patch. Bigger files/streams cause the read to fail.
 const MAX_PATCH_BYTES: usize = 10 * 1024;
 
-/// If source is specified, read from the provided file and send it as a settings patch to the daemon.
-/// Otherwise, read the patch from standard input.
+/// If source is specified, read from the provided file and send it as a settings patch to the
+/// daemon. Otherwise, read the patch from standard input.
 pub async fn import(source: String) -> Result<()> {
     let json_blob = tokio::task::spawn_blocking(|| get_blob(source))
         .await
@@ -26,10 +26,28 @@ pub async fn import(source: String) -> Result<()> {
     Ok(())
 }
 
+/// If source is specified, write a patch to the file. Otherwise, write the patch to standard
+/// output.
+pub async fn export(dest: String) -> Result<()> {
+    let mut rpc = MullvadProxyClient::new().await?;
+    let json_blob = rpc
+        .export_json_settings()
+        .await
+        .context("Error exporting patch")?;
+
+    tokio::task::spawn_blocking(|| put_blob(dest, json_blob))
+        .await
+        .unwrap()?;
+
+    Ok(())
+}
+
 fn get_blob(source: String) -> Result<String> {
     match source.as_str() {
         "-" => read_settings_from_stdin().context("Failed to read from stdin"),
-        _ => read_settings_from_file(source).context("Failed to read from path: {source}"),
+        _ => {
+            read_settings_from_file(&source).context(format!("Failed to read from path: {source}"))
+        }
     }
 }
 
@@ -99,3 +117,30 @@ fn read_settings_from_reader(mut reader: impl BufRead) -> Result<String> {
         .context("settings must be utf8 encoded")?
         .to_owned())
 }
+
+fn put_blob(dest: String, blob: String) -> Result<()> {
+    match dest.as_str() {
+        "-" => write_settings_to_stdout(blob).context("Failed to write to stdout"),
+        _ => write_settings_to_file(&dest, blob).context(format!("Failed to write to path {dest}")),
+    }
+}
+
+/// Write patch to standard output
+fn write_settings_to_stdout(blob: String) -> Result<()> {
+    write_settings_using_writer(BufWriter::new(stdout()), blob)
+}
+
+/// Write patch to path
+fn write_settings_to_file(path: impl AsRef<Path>, blob: String) -> Result<()> {
+    write_settings_using_writer(
+        BufWriter::new(File::options().create(true).write(true).open(path)?),
+        blob,
+    )
+}
+
+fn write_settings_using_writer(mut writer: impl Write, blob: String) -> Result<()> {
+    writer
+        .write_all(blob.as_bytes())
+        .context("Failed to write blob to destination")?;
+    writer.write_all(b"\n").context("Failed to write newline")
+}
diff --git a/mullvad-cli/src/main.rs b/mullvad-cli/src/main.rs
index a5887b39d5..c051f0246f 100644
--- a/mullvad-cli/src/main.rs
+++ b/mullvad-cli/src/main.rs
@@ -138,11 +138,17 @@ enum Cli {
     #[clap(subcommand)]
     CustomList(custom_list::CustomList),
 
-    /// Apply a JSON patch
+    /// Apply a JSON patch generated by 'export-settings'
     ImportSettings {
         /// File to read from. If this is "-", read from standard input
         file: String,
     },
+
+    /// Export a JSON patch based on the current settings
+    ExportSettings {
+        /// File to write to. If this is "-", write to standard output
+        file: String,
+    },
 }
 
 #[tokio::main]
@@ -170,6 +176,7 @@ async fn main() -> Result<()> {
         Cli::Status { cmd, args } => status::handle(cmd, args).await,
         Cli::CustomList(cmd) => cmd.handle().await,
         Cli::ImportSettings { file } => patch::import(file).await,
+        Cli::ExportSettings { file } => patch::export(file).await,
 
         #[cfg(all(unix, not(target_os = "android")))]
         Cli::ShellCompletions { shell, dir } => {