- Initial commit

Runtime/HTTP/Request/Upload/Forms/UrlEncodedStream.cs

@@ -0,0 +1,158 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+using Best.HTTP.Shared.PlatformSupport.Text;
+
+namespace Best.HTTP.Request.Upload.Forms
+{
+    /// <summary>
+    /// Readonly struct to hold key -> value pairs, where the value is either textual or binary.
+    /// </summary>
+    readonly struct FormField
+    {
+        public readonly string Key;
+        public readonly string TextValue;
+        public readonly byte[] BinaryValue;
+
+        public FormField(string key, string textValue)
+        {
+            this.Key = key;
+            this.TextValue = textValue;
+            this.BinaryValue = null;
+        }
+
+        public FormField(string key, byte[] binaryValue)
+        {
+            this.Key = key;
+            this.TextValue = null;
+            this.BinaryValue = binaryValue;
+        }
+    }
+
+    /// <summary>
+    /// An <see cref="UploadStreamBase"/> implementation representing a stream that prepares and sends data as URL-encoded form data in an HTTP request.
+    /// </summary>
+    /// <remarks>
+    /// <para>This stream is used to send data as URL-encoded form data in an HTTP request. It sets the <c>"Content-Type"</c> header to <c>"application/x-www-form-urlencoded"</c>.
+    /// URL-encoded form data is typically used for submitting form data to a web server. It is commonly used in HTTP POST requests to send data to a server, such as submitting HTML form data.</para>
+    /// 
+    /// <para>The return value of <see cref="System.IO.Stream.Read(byte[], int, int)"/> is treated specially in the plugin:
+    /// <list type="bullet">
+    ///     <item>
+    ///         <term>Less than zero(<c>-1</c>) value </term>
+    ///         <description> indicates that no data is currently available but more is expected in the future. In this case, when new data becomes available the IThreadSignaler object must be signaled.</description>
+    ///     </item>
+    ///     <item>
+    ///         <term>Zero (<c>0</c>)</term>
+    ///         <description> means that the stream is closed, no more data can be expected.</description>
+    ///     </item>
+    /// </list>
+    /// A zero value to signal stream closure can follow a less than zero value.</para>
+    /// <para>While it's possible, it's not advised to send binary data url-encoded!</para>
+    /// </remarks>
+    public sealed class UrlEncodedStream : UploadStreamBase
+    {
+        private const int EscapeTreshold = 256;
+
+        /// <summary>
+        /// Gets the length of the stream.
+        /// </summary>
+        public override long Length { get => this._memoryStream.Length; }
+
+        private MemoryStream _memoryStream;
+
+        /// <summary>
+        /// A list that holds the form's fields.
+        /// </summary>
+        private List<FormField> _fields = new List<FormField>();
+
+        /// <summary>
+        /// Sets up the HTTP request by adding the <c>"Content-Type"</c> header as <c>"application/x-www-form-urlencoded"</c>.
+        /// </summary>
+        /// <param name="request">The HTTP request.</param>
+        public override void BeforeSendHeaders(HTTPRequest request)
+        {
+            request.SetHeader("Content-Type", "application/x-www-form-urlencoded");
+
+            StringBuilder sb = StringBuilderPool.Get(_fields.Count * 4);
+
+            // Create a "field1=value1&field2=value2" formatted string
+            for (int i = 0; i < _fields.Count; ++i)
+            {
+                var field = _fields[i];
+
+                if (i > 0)
+                    sb.Append("&");
+
+                sb.Append(EscapeString(field.Key));
+                sb.Append("=");
+
+                if (!string.IsNullOrEmpty(field.TextValue) || field.BinaryValue == null)
+                    sb.Append(EscapeString(field.TextValue));
+                else
+                    // If forced to this form type with binary data, we will create a base64 encoded string from it.
+                    sb.Append(Convert.ToBase64String(field.BinaryValue, 0, field.BinaryValue.Length));
+            }
+
+            this._memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(StringBuilderPool.ReleaseAndGrab(sb)));
+        }
+
+        /// <summary>
+        /// Adds binary data to the form. It is not advised to send binary data with an URL-encoded form due to the conversion cost of binary to text conversion.
+        /// </summary>
+        /// <param name="fieldName">The name of the field.</param>
+        /// <param name="content">The binary data content.</param>
+        /// <returns>The UrlEncodedStream instance for method chaining.</returns>
+        public UrlEncodedStream AddBinaryData(string fieldName, byte[] content)
+        {
+            _fields.Add(new FormField(fieldName, content));
+
+            return this;
+        }
+
+        public UrlEncodedStream AddField(string fieldName, string value)
+        {
+            _fields.Add(new FormField(fieldName, value));
+
+            return this;
+        }
+
+        public override int Read(byte[] buffer, int offset, int count) => this._memoryStream.Read(buffer, offset, count);
+
+        private static string EscapeString(string originalString)
+        {
+            if (originalString.Length < EscapeTreshold)
+                return Uri.EscapeDataString(originalString);
+            else
+            {
+                int loops = originalString.Length / EscapeTreshold;
+                StringBuilder sb = StringBuilderPool.Get(loops); //new StringBuilder(loops);
+
+                for (int i = 0; i <= loops; i++)
+                    sb.Append(i < loops ?
+                                 Uri.EscapeDataString(originalString.Substring(EscapeTreshold * i, EscapeTreshold)) :
+                                 Uri.EscapeDataString(originalString.Substring(EscapeTreshold * i)));
+                return StringBuilderPool.ReleaseAndGrab(sb);
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+
+            this._memoryStream?.Dispose();
+            this._memoryStream = null;
+        }
+
+        public override bool CanRead => true;
+        public override bool CanSeek => false;
+        public override bool CanWrite => false;
+        public override long Position { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+        public override long Seek(long offset, SeekOrigin origin) => throw new NotImplementedException();
+        public override void SetLength(long value) => throw new NotImplementedException();
+        public override void Write(byte[] buffer, int offset, int count) => throw new NotImplementedException();
+        public override void Flush() => throw new NotImplementedException();
+    }
+}