Telegram markdown support for structured json messages

shared/src/utils/json_utils.rs

@@ -3,6 +3,7 @@ use std::io::{self, Read};
 use serde::de::DeserializeOwned;
 use serde::{Deserialize};
 use serde_json::{self, Deserializer, Value};
+use crate::utils::humanize_snake_case;
 
 fn read_skipping_ws(mut reader: impl Read) -> io::Result<u8> {
     loop {
@@ -166,4 +167,52 @@ where
 {
     let value: Option<String> = Option::deserialize(deserializer)?;
     Ok(value.unwrap_or_default())
+}
+
+const MARKDOWN_SPECIAL_CHARS: &str = r#"_*[]()~`>#+-=|{}.!\"#;
+
+fn escape_markdown_v2(text: &str) -> String {
+    let mut escaped = String::new();
+    for c in text.chars() {
+        if MARKDOWN_SPECIAL_CHARS.contains(c) {
+            escaped.push('\\');
+        }
+        escaped.push(c);
+    }
+    escaped
+}
+
+fn json_to_markdown(value: &Value) -> String {
+    fn format_value(v: &Value, indent: usize) -> String {
+        let pad = "  ".repeat(indent);
+        match v {
+            Value::Object(map) => map.iter()
+                .map(|(k, v)| {
+                    let formatted = format_value(v, indent + 1);
+                    let key = humanize_snake_case(k);
+                    if v.is_object() || v.is_array() {
+                        format!("{pad}*{key}:*\n{formatted}")
+                    } else {
+                        format!("{pad}*{key}:* {formatted}")
+                    }
+                })
+                .collect::<Vec<_>>()
+                .join("\n"),
+            Value::Array(arr) => arr.iter()
+                .map(|v| format!("{pad}\\- {}", format_value(v, indent + 1).trim()))
+                .collect::<Vec<_>>()
+                .join("\n"),
+            Value::String(s) => escape_markdown_v2(s),
+            Value::Number(n) => escape_markdown_v2(&n.to_string()),
+            Value::Bool(b) => b.to_string(),
+            Value::Null => "null".to_string(),
+        }
+    }
+
+    format_value(value, 0)
+}
+
+pub fn json_str_to_markdown(json_str: &str) -> Result<String, serde_json::Error> {
+    let value: Value = serde_json::from_str(json_str)?;
+    Ok(json_to_markdown(&value))
 }

shared/src/utils/string_utils.rs

@@ -106,6 +106,27 @@ pub fn mask_credentials(s: &str) -> String {
     }
 }
 
+pub fn humanize_snake_case(s: &str) -> String {
+    let mut result = String::with_capacity(s.len());
+    let mut capitalize_next = true;
+
+    for c in s.chars() {
+        if c == '_' {
+            result.push(' ');
+            capitalize_next = true;
+        } else if capitalize_next {
+            for up in c.to_uppercase() {
+                result.push(up);
+            }
+            capitalize_next = false;
+        } else {
+            result.push(c);
+        }
+    }
+
+    result
+}
+
 #[cfg(test)]
 mod test {
     use std::collections::HashSet;