diff --git a/src/database/entry.rs b/src/database/entry.rs
index 173bf79..e14ff3b 100644
--- a/src/database/entry.rs
+++ b/src/database/entry.rs
@@ -28,6 +28,7 @@ pub enum EntryValue {
     String(String),
     Number(f64),
     Address(Address),
+    Null,
     Invalid,
 }
 
@@ -151,6 +152,7 @@ impl EntryValue {
             EntryValue::String(value) => ('S', value.to_owned()),
             EntryValue::Number(n) => ('N', n.to_string()),
             EntryValue::Address(address) => ('O', address.to_string()),
+            EntryValue::Null => ('X', "".to_string()),
             EntryValue::Invalid => return Err(anyhow!("Cannot serialize invalid value.")),
         };
 
@@ -163,10 +165,10 @@ impl std::str::FromStr for EntryValue {
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         if s.len() < 2 {
-            if s.starts_with('S') {
-                Ok(EntryValue::String("".into()))
-            } else {
-                Ok(EntryValue::Invalid)
+            match s.chars().next() {
+                Some('S') => Ok(EntryValue::String("".into())),
+                Some('X') => Ok(EntryValue::Null),
+                _ => Ok(EntryValue::Invalid),
             }
         } else {
             let (type_char, content) = s.split_at(1);
@@ -198,6 +200,7 @@ impl std::fmt::Display for EntryValue {
             EntryValue::Address(address) => ("ADDRESS", address.to_string()),
             EntryValue::String(string) => ("STRING", string.to_owned()),
             EntryValue::Number(n) => ("NUMBER", n.to_string()),
+            EntryValue::Null => ("NULL", "NULL".to_string()),
             EntryValue::Invalid => ("INVALID", "INVALID".to_string()),
         };
         write!(f, "{}: {}", entry_type, entry_value)
@@ -255,6 +258,11 @@ mod tests {
         let decoded = encoded.parse::<EntryValue>()?;
         assert_eq!(entry, decoded);
 
+        let entry = EntryValue::Null;
+        let encoded = entry.to_string()?;
+        let decoded = encoded.parse::<EntryValue>()?;
+        assert_eq!(entry, decoded);
+
         Ok(())
     }
 
diff --git a/src/extractors/audio.rs b/src/extractors/audio.rs
new file mode 100644
index 0000000..b6d7945
--- /dev/null
+++ b/src/extractors/audio.rs
@@ -0,0 +1,25 @@
+use super::Extractor;
+use crate::{
+    addressing::Address,
+    database::{entry::Entry, UpEndConnection},
+    util::jobs::{Job, JobContainer, State},
+};
+use actix_web::web;
+use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+use std::sync::{Arc, Mutex, RwLock};
+use webpage::{Webpage, WebpageOptions};
+
+pub struct ID3Extractor;
+
+#[async_trait]
+impl Extractor for ID3Extractor {
+    async fn get(
+        &self,
+        address: Address,
+        connection: Arc<Mutex<UpEndConnection>>,
+        job_container: Arc<RwLock<JobContainer>>,
+    ) -> Result<Vec<Entry>> {
+        todo!();
+    }
+}