Use blocking reqwest API in defer

defer, or, trait functions such as it in general(?) cannot be async (yet)

plume-common/Cargo.toml

@@ -16,7 +16,6 @@ hex = "0.3"
 hyper = "0.13"
 openssl = "0.10.22"
 rocket = { git = "https://github.com/SergioBenitez/Rocket", rev = "async" }
-reqwest = "0.10"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
@@ -32,3 +31,7 @@ version = "0.4"
 [dependencies.pulldown-cmark]
 default-features = false
 version = "0.2.0"
+
+[dependencies.reqwest]
+features = ["json", "blocking"]
+version = "0.10"

plume-common/src/activity_pub/inbox.rs

@@ -279,7 +279,8 @@ pub trait FromId<C>: Sized {
 
     /// Dereferences an ID
     fn deref(id: &str) -> Result<Self::Object, (Option<serde_json::Value>, Self::Error)> {
-        reqwest::ClientBuilder::new()
+        // Use blocking reqwest API here, since defer cannot be async (yet)
+        reqwest::blocking::Client::builder()
             .connect_timeout(std::time::Duration::from_secs(5))
             .build()
             .map_err(|_| (None, InboxError::DerefError.into()))?