Can check whether two users are friends or not

src/helpers/database.rs

@@ -136,6 +136,17 @@ impl<'a> RowResult<'a> {
         }
     }
 
+    /// Find an integer included in the request
+    pub fn get_usize(&self, name: &str) -> Result<usize, Box<dyn Error>> {
+        let value = self.row.get_opt(self.find_col(name)?);
+
+        match value {
+            None => Err(ExecError::boxed_string(
+                format!("Could not extract integer field {} !", name))),
+            Some(s) => Ok(s?)
+        }
+    }
+
     /// Find a string included in the request
     pub fn get_str(&self, name: &str) -> Result<String, Box<dyn Error>> {
         let value = self.row.get_opt(self.find_col(name)?);
@@ -245,6 +256,15 @@ pub fn query<E, F: Fn(&RowResult) -> ProcessRowResult<E>>(info: QueryInfo, proce
     Ok(res)
 }
 
+/// Count the number of results a query would have produced
+pub fn count(mut q: QueryInfo) -> ResultBoxError<usize> {
+    &q.fields.clear();
+    &q.fields.push("COUNT(*) as count".to_string());
+
+    query(q, |res| res.get_usize("count"))?.pop()
+        .ok_or(ExecError::boxed_new("database::count did not return a result!"))
+}
+
 /// Structure used to execute a insert query
 pub struct InsertQuery {
     pub table: String,

src/helpers/friends_helper.rs

@@ -0,0 +1,18 @@
+//! # Friends helper
+//!
+//! @author Pierre Hubert
+
+
+use crate::data::user::UserID;
+use crate::data::error::ResultBoxError;
+use crate::helpers::database;
+use crate::constants::database_tables_names::FRIENDS_TABLE;
+use crate::helpers::database::QueryInfo;
+
+/// Check out whether two users are friend or not
+pub fn are_friend(user_one: UserID, user_two: UserID) -> ResultBoxError<bool> {
+    Ok(database::count(QueryInfo::new(FRIENDS_TABLE)
+        .cond_i64("ID_personne", user_one)
+        .cond_i64("ID_amis", user_two)
+        .cond_i64("actif", 1))? > 0)
+}

src/helpers/mod.rs

@@ -2,4 +2,5 @@ pub mod database;
 
 pub mod api_helper;
 pub mod account_helper;
-pub mod user_helper;
+pub mod user_helper;
+pub mod friends_helper;