diff --git a/plume-common/src/activity_pub/mod.rs b/plume-common/src/activity_pub/mod.rs
index 82514cd0..374ef9bf 100644
--- a/plume-common/src/activity_pub/mod.rs
+++ b/plume-common/src/activity_pub/mod.rs
@@ -4,6 +4,7 @@ use activitystreams::{
     iri_string::types::IriString,
     markers::Activity as Activity07,
     object::{ApObject, Article},
+    primitives::{AnyString, OneOrMany},
     unparsed::UnparsedMutExt,
 };
 use activitystreams_ext::{Ext1, UnparsedExtension};
@@ -407,6 +408,27 @@ where
 
 pub type LicensedArticle = Ext1<ApObject<Article>, Licensed07>;
 
+pub trait ToAsString {
+    fn to_as_string(&self) -> Option<String>;
+}
+
+impl ToAsString for OneOrMany<&AnyString> {
+    fn to_as_string(&self) -> Option<String> {
+        if let Some(prop) = self.as_one() {
+            prop.as_xsd_string()
+                .or_else(|| prop.as_rdf_lang_string().map(|ls| ls.value.as_str()))
+        } else if let Some(props) = self.as_many() {
+            props.iter().next().and_then(|prop| {
+                prop.as_xsd_string()
+                    .or_else(|| prop.as_rdf_lang_string().map(|ls| ls.value.as_str()))
+            })
+        } else {
+            None
+        }
+        .map(|s| s.to_string())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;