From 955434a8c86cf8a2ae7e4d62e67441e281398d46 Mon Sep 17 00:00:00 2001
From: stuebinm
Date: Wed, 30 Nov 2022 23:19:18 +0100
Subject: way to elaborate error messages

(but miette is fun!)
---
 src/main.rs | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

(limited to 'src/main.rs')

diff --git a/src/main.rs b/src/main.rs
index 81a5067..feb6e9c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,9 @@ use protos::protos::gtfs_realtime::FeedMessage;
 
 use protobuf::Message;
 use clap::Parser;
+// use anyhow::Context;
+use miette::{WrapErr, IntoDiagnostic, miette};
+use reqwest::header::{HeaderValue, CONTENT_TYPE};
 
 #[derive(Parser, Debug)]
 #[command(author, version, about, long_about = None)]
@@ -12,22 +15,42 @@ struct Args {
    url: String,
    /// emit the feed as json
    #[arg(long)]
-   json: bool
+   json: bool,
+   #[arg(long="ignore-nonfatal", short='i')]
+   ignore_nonfatal: bool
 }
 
 
 #[tokio::main]
-async fn main() -> Result<(), Box<dyn std::error::Error>> {
+async fn main() -> miette::Result<()> {
+
     let args = Args::parse();
     let resp = reqwest::get(&args.url)
-        .await?
-        .bytes().await?;
+        .await.into_diagnostic().wrap_err("Request failed")?
+        .error_for_status().into_diagnostic()?;
+
+    if !args.ignore_nonfatal {
+        let ct = HeaderValue::from_static("application/octet-stream");
+        match resp.headers().get(CONTENT_TYPE) {
+            Some(content_type) if ct == content_type => (),
+            Some(other_type) =>
+                Err(miette!("should be {:?}", ct))
+                  .wrap_err(format!("Bad Content-Type {:?}", other_type))?,
+            None =>
+                Err(miette!("Content-Type header is missing"))?
+        }
+    }
+
+    let resp = resp
+        .bytes().await.into_diagnostic()?;
 
-    let proto = FeedMessage::parse_from_bytes(&resp[..])?;
+    let proto = FeedMessage::parse_from_bytes(&resp[..])
+        .into_diagnostic()
+        .wrap_err("Could not parse protobuf format")?;
 
     match args.json {
         true => 
-            println!("{}", protobuf_json_mapping::print_to_string(&proto)?),
+            println!("{}", protobuf_json_mapping::print_to_string(&proto).into_diagnostic()?),
         false => 
             println!("{}", protobuf::text_format::print_to_string_pretty(&proto))
     }
-- 
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