From 91b43790b3135675977af25c8462b9b6614655cb Mon Sep 17 00:00:00 2001
From: Oliver Booth <me@olivr.me>
Date: Wed, 20 Apr 2022 15:17:33 +0100
Subject: [PATCH] Add selector parameter for key, value, or both (resolves #3)

Allows caller to specify a transformation to apply to key/value, presumably when either (or both) do not have an intended result of ToString
---
 .../DictionaryExtensions.cs                   | 163 ++++++++++++++++--
 1 file changed, 153 insertions(+), 10 deletions(-)

diff --git a/X10D/src/DictionaryExtensions/DictionaryExtensions.cs b/X10D/src/DictionaryExtensions/DictionaryExtensions.cs
index abb09eb..60306eb 100644
--- a/X10D/src/DictionaryExtensions/DictionaryExtensions.cs
+++ b/X10D/src/DictionaryExtensions/DictionaryExtensions.cs
@@ -29,20 +29,90 @@ public static class DictionaryExtensions
                 return string.Empty;
             }
 
-            foreach (char character in value)
-            {
-                if (char.IsWhiteSpace(character))
-                {
-                    return $"\"{value}\"";
-                }
-            }
-
-            return value;
+            return value.Contains(' ') ? $"\"{value}\"" : value;
         }
 
         static string GetQueryParameter(KeyValuePair<TKey, TValue> pair)
         {
-            return $"{pair.Key}={SanitizeValue(pair.Value?.ToString())}");
+            return $"{pair.Key}={SanitizeValue(pair.Value?.ToString())}";
+        }
+
+        return string.Join(';', source.Select(GetQueryParameter));
+    }
+
+    /// <summary>
+    ///     Converts an <see cref="IEnumerable{T}" /> of <see cref="KeyValuePair{TKey, TValue}" /> to an data connection
+    ///     string.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the key element of the key/value pair.</typeparam>
+    /// <typeparam name="TValue">The type of the value element of the key/value pair.</typeparam>
+    /// <param name="source">The source dictionary.</param>
+    /// <param name="selector">
+    ///     A transform function to apply to the <see cref="KeyValuePair{TKey,TValue}.Value" /> of each element.
+    /// </param>
+    /// <returns>A <see cref="string" /> representing the dictionary as a key=value set, concatenated with <c>;</c>.</returns>
+    public static string ToConnectionString<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> source,
+        Func<TValue, string?> selector)
+    {
+        if (source is null)
+        {
+            throw new ArgumentNullException(nameof(source));
+        }
+
+        static string SanitizeValue(string? value)
+        {
+            if (value is null)
+            {
+                return string.Empty;
+            }
+
+            return value.Contains(' ') ? $"\"{value}\"" : value;
+        }
+
+        string GetQueryParameter(KeyValuePair<TKey, TValue> pair)
+        {
+            return $"{pair.Key}={SanitizeValue(selector(pair.Value))}";
+        }
+
+        return string.Join(';', source.Select(GetQueryParameter));
+    }
+
+    /// <summary>
+    ///     Converts an <see cref="IEnumerable{T}" /> of <see cref="KeyValuePair{TKey, TValue}" /> to an data connection
+    ///     string.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the key element of the key/value pair.</typeparam>
+    /// <typeparam name="TValue">The type of the value element of the key/value pair.</typeparam>
+    /// <param name="source">The source dictionary.</param>
+    /// <param name="keySelector">
+    ///     A transform function to apply to the <see cref="KeyValuePair{TKey,TValue}.Key" /> of each element.
+    /// </param>
+    /// <param name="valueSelector">
+    ///     A transform function to apply to the <see cref="KeyValuePair{TKey,TValue}.Value" /> of each element.
+    /// </param>
+    /// <returns>A <see cref="string" /> representing the dictionary as a key=value set, concatenated with <c>;</c>.</returns>
+    public static string ToConnectionString<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> source,
+        Func<TKey, string> keySelector, Func<TValue, string?> valueSelector)
+        where TKey : notnull
+    {
+        if (source is null)
+        {
+            throw new ArgumentNullException(nameof(source));
+        }
+
+        static string SanitizeValue(string? value)
+        {
+            if (value is null)
+            {
+                return string.Empty;
+            }
+
+            return value.Contains(' ') ? $"\"{value}\"" : value;
+        }
+
+        string GetQueryParameter(KeyValuePair<TKey, TValue> pair)
+        {
+            return $"{keySelector(pair.Key)}={SanitizeValue(valueSelector(pair.Value))}";
         }
 
         return string.Join(';', source.Select(GetQueryParameter));
@@ -72,4 +142,77 @@ public static class DictionaryExtensions
 
         return string.Join('&', source.Select(GetQueryParameter));
     }
+
+    /// <summary>
+    ///     Converts an <see cref="IEnumerable{T}" /> of <see cref="KeyValuePair{TKey, TValue}" /> to a HTTP GET query string.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the key element of the key/value pair.</typeparam>
+    /// <typeparam name="TValue">The type of the value element of the key/value pair.</typeparam>
+    /// <param name="source">The source dictionary.</param>
+    /// <param name="selector">
+    ///     A transform function to apply to the <see cref="KeyValuePair{TKey,TValue}.Value" /> of each element.
+    /// </param>
+    /// <returns>A <see cref="string" /> representing the dictionary as a key=value set, concatenated with <c>&amp;</c>.</returns>
+    public static string ToGetParameters<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> source,
+        Func<TValue, string?> selector)
+        where TKey : notnull
+    {
+        if (source is null)
+        {
+            throw new ArgumentNullException(nameof(source));
+        }
+
+        if (selector is null)
+        {
+            throw new ArgumentNullException(nameof(selector));
+        }
+
+        // can't static here because of 'selector' parameter
+        string GetQueryParameter(KeyValuePair<TKey, TValue> pair)
+        {
+            string key = HttpUtility.UrlEncode(pair.Key.ToString())!;
+            string? value = HttpUtility.UrlEncode(selector(pair.Value));
+            return $"{key}={value}";
+        }
+
+        return string.Join('&', source.Select(GetQueryParameter));
+    }
+
+    /// <summary>
+    ///     Converts an <see cref="IEnumerable{T}" /> of <see cref="KeyValuePair{TKey, TValue}" /> to a HTTP GET query string.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the key element of the key/value pair.</typeparam>
+    /// <typeparam name="TValue">The type of the value element of the key/value pair.</typeparam>
+    /// <param name="source">The source dictionary.</param>
+    /// <param name="keySelector">
+    ///     A transform function to apply to the <see cref="KeyValuePair{TKey,TValue}.Key" /> of each element.
+    /// </param>
+    /// <param name="valueSelector">
+    ///     A transform function to apply to the <see cref="KeyValuePair{TKey,TValue}.Value" /> of each element.
+    /// </param>
+    /// <returns>A <see cref="string" /> representing the dictionary as a key=value set, concatenated with <c>&amp;</c>.</returns>
+    public static string ToGetParameters<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> source,
+        Func<TKey, string> keySelector, Func<TValue, string?> valueSelector)
+        where TKey : notnull
+    {
+        if (source is null)
+        {
+            throw new ArgumentNullException(nameof(source));
+        }
+
+        if (valueSelector is null)
+        {
+            throw new ArgumentNullException(nameof(valueSelector));
+        }
+
+        // can't static here because of selector parameters
+        string GetQueryParameter(KeyValuePair<TKey, TValue> pair)
+        {
+            string key = HttpUtility.UrlEncode(keySelector(pair.Key));
+            string? value = HttpUtility.UrlEncode(valueSelector(pair.Value));
+            return $"{key}={value}";
+        }
+
+        return string.Join('&', source.Select(GetQueryParameter));
+    }
 }