From 86778d06b192f0c1bc57eedcdf3fcf2cb3962052 Mon Sep 17 00:00:00 2001
From: Carlos Esquerdo Bernat <esquerbatua@gmail.com>
Date: Mon, 7 Jun 2021 10:18:40 +0200
Subject: [PATCH] net.http: add a Header.starting_with method, to get the first
 header, starting with a key (#10119)

---
 vlib/net/http/header.v      | 10 ++++++++++
 vlib/net/http/header_test.v |  8 ++++++++
 2 files changed, 18 insertions(+)

diff --git a/vlib/net/http/header.v b/vlib/net/http/header.v
index 4069d5c434..bab883a069 100644
--- a/vlib/net/http/header.v
+++ b/vlib/net/http/header.v
@@ -469,6 +469,16 @@ pub fn (h Header) get_custom(key string, flags ...HeaderQueryConfig) ?string {
 	return h.data[data_key][0]
 }
 
+// Gets the first value of the header starting with key, or none if the key does not exist.
+pub fn (h Header) starting_with(key string) ?string {
+	for k, _ in h.data {
+		if k.starts_with(key) {
+			return k
+		}
+	}
+	return none
+}
+
 // Gets all values for the CommonHeader.
 pub fn (h Header) values(key CommonHeader) []string {
 	return h.custom_values(key.str())
diff --git a/vlib/net/http/header_test.v b/vlib/net/http/header_test.v
index 3426113430..a7ee6ea793 100644
--- a/vlib/net/http/header_test.v
+++ b/vlib/net/http/header_test.v
@@ -115,6 +115,14 @@ fn test_get_custom() ? {
 	}
 }
 
+fn test_starting_with() ? {
+	mut h := http.new_header()
+	h.add_custom('Hello-1', 'world') ?
+	h.add_custom('Hello-21', 'world') ?
+	assert h.starting_with('Hello-') ? == 'Hello-1'
+	assert h.starting_with('Hello-2') ? == 'Hello-21'
+}
+
 fn test_custom_values() ? {
 	mut h := http.new_header()
 	h.add_custom('Hello', 'world') ?