aspnetcore/src/Http/Http.Abstractions/src/PathString.cs

494 lines
20 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.ComponentModel;
using System.Globalization;
using System.Text;
using Microsoft.AspNetCore.Http.Abstractions;
using Microsoft.AspNetCore.Http.Internal;
namespace Microsoft.AspNetCore.Http
{
/// <summary>
/// Provides correct escaping for Path and PathBase values when needed to reconstruct a request or redirect URI string
/// </summary>
[TypeConverter(typeof(PathStringConverter))]
public readonly struct PathString : IEquatable<PathString>
{
/// <summary>
/// Represents the empty path. This field is read-only.
/// </summary>
public static readonly PathString Empty = new PathString(string.Empty);
private readonly string _value;
/// <summary>
/// Initialize the path string with a given value. This value must be in unescaped format. Use
/// PathString.FromUriComponent(value) if you have a path value which is in an escaped format.
/// </summary>
/// <param name="value">The unescaped path to be assigned to the Value property.</param>
public PathString(string value)
{
if (!string.IsNullOrEmpty(value) && value[0] != '/')
{
throw new ArgumentException(Resources.FormatException_PathMustStartWithSlash(nameof(value)), nameof(value));
}
_value = value;
}
/// <summary>
/// The unescaped path value
/// </summary>
public string Value
{
get { return _value; }
}
/// <summary>
/// True if the path is not empty
/// </summary>
public bool HasValue
{
get { return !string.IsNullOrEmpty(_value); }
}
/// <summary>
/// Provides the path string escaped in a way which is correct for combining into the URI representation.
/// </summary>
/// <returns>The escaped path value</returns>
public override string ToString()
{
return ToUriComponent();
}
/// <summary>
/// Provides the path string escaped in a way which is correct for combining into the URI representation.
/// </summary>
/// <returns>The escaped path value</returns>
public string ToUriComponent()
{
if (!HasValue)
{
return string.Empty;
}
var value = _value;
var i = 0;
for (; i < value.Length; i++)
{
if (!PathStringHelper.IsValidPathChar(value[i]) || PathStringHelper.IsPercentEncodedChar(value, i))
{
break;
}
}
if (i < value.Length)
{
return ToEscapedUriComponent(value, i);
}
return value;
}
private static string ToEscapedUriComponent(string value, int i)
{
StringBuilder buffer = null;
var start = 0;
var count = i;
var requiresEscaping = false;
while (i < value.Length)
{
var isPercentEncodedChar = PathStringHelper.IsPercentEncodedChar(value, i);
if (PathStringHelper.IsValidPathChar(value[i]) || isPercentEncodedChar)
{
if (requiresEscaping)
{
// the current segment requires escape
if (buffer == null)
{
buffer = new StringBuilder(value.Length * 3);
}
buffer.Append(Uri.EscapeDataString(value.Substring(start, count)));
requiresEscaping = false;
start = i;
count = 0;
}
if (isPercentEncodedChar)
{
count += 3;
i += 3;
}
else
{
count++;
i++;
}
}
else
{
if (!requiresEscaping)
{
// the current segment doesn't require escape
if (buffer == null)
{
buffer = new StringBuilder(value.Length * 3);
}
buffer.Append(value, start, count);
requiresEscaping = true;
start = i;
count = 0;
}
count++;
i++;
}
}
if (count == value.Length && !requiresEscaping)
{
return value;
}
else
{
if (count > 0)
{
if (buffer == null)
{
buffer = new StringBuilder(value.Length * 3);
}
if (requiresEscaping)
{
buffer.Append(Uri.EscapeDataString(value.Substring(start, count)));
}
else
{
buffer.Append(value, start, count);
}
}
return buffer.ToString();
}
}
/// <summary>
/// Returns an PathString given the path as it is escaped in the URI format. The string MUST NOT contain any
/// value that is not a path.
/// </summary>
/// <param name="uriComponent">The escaped path as it appears in the URI format.</param>
/// <returns>The resulting PathString</returns>
public static PathString FromUriComponent(string uriComponent)
{
// REVIEW: what is the exactly correct thing to do?
return new PathString(Uri.UnescapeDataString(uriComponent));
}
/// <summary>
/// Returns an PathString given the path as from a Uri object. Relative Uri objects are not supported.
/// </summary>
/// <param name="uri">The Uri object</param>
/// <returns>The resulting PathString</returns>
public static PathString FromUriComponent(Uri uri)
{
if (uri == null)
{
throw new ArgumentNullException(nameof(uri));
}
// REVIEW: what is the exactly correct thing to do?
return new PathString("/" + uri.GetComponents(UriComponents.Path, UriFormat.Unescaped));
}
/// <summary>
/// Determines whether the beginning of this <see cref="PathString"/> instance matches the specified <see cref="PathString"/>.
/// </summary>
/// <param name="other">The <see cref="PathString"/> to compare.</param>
/// <returns>true if value matches the beginning of this string; otherwise, false.</returns>
public bool StartsWithSegments(PathString other)
{
return StartsWithSegments(other, StringComparison.OrdinalIgnoreCase);
}
/// <summary>
/// Determines whether the beginning of this <see cref="PathString"/> instance matches the specified <see cref="PathString"/> when compared
/// using the specified comparison option.
/// </summary>
/// <param name="other">The <see cref="PathString"/> to compare.</param>
/// <param name="comparisonType">One of the enumeration values that determines how this <see cref="PathString"/> and value are compared.</param>
/// <returns>true if value matches the beginning of this string; otherwise, false.</returns>
public bool StartsWithSegments(PathString other, StringComparison comparisonType)
{
var value1 = Value ?? string.Empty;
var value2 = other.Value ?? string.Empty;
if (value1.StartsWith(value2, comparisonType))
{
return value1.Length == value2.Length || value1[value2.Length] == '/';
}
return false;
}
/// <summary>
/// Determines whether the beginning of this <see cref="PathString"/> instance matches the specified <see cref="PathString"/> and returns
/// the remaining segments.
/// </summary>
/// <param name="other">The <see cref="PathString"/> to compare.</param>
/// <param name="remaining">The remaining segments after the match.</param>
/// <returns>true if value matches the beginning of this string; otherwise, false.</returns>
public bool StartsWithSegments(PathString other, out PathString remaining)
{
return StartsWithSegments(other, StringComparison.OrdinalIgnoreCase, out remaining);
}
/// <summary>
/// Determines whether the beginning of this <see cref="PathString"/> instance matches the specified <see cref="PathString"/> when compared
/// using the specified comparison option and returns the remaining segments.
/// </summary>
/// <param name="other">The <see cref="PathString"/> to compare.</param>
/// <param name="comparisonType">One of the enumeration values that determines how this <see cref="PathString"/> and value are compared.</param>
/// <param name="remaining">The remaining segments after the match.</param>
/// <returns>true if value matches the beginning of this string; otherwise, false.</returns>
public bool StartsWithSegments(PathString other, StringComparison comparisonType, out PathString remaining)
{
var value1 = Value ?? string.Empty;
var value2 = other.Value ?? string.Empty;
if (value1.StartsWith(value2, comparisonType))
{
if (value1.Length == value2.Length || value1[value2.Length] == '/')
{
remaining = new PathString(value1.Substring(value2.Length));
return true;
}
}
remaining = Empty;
return false;
}
/// <summary>
/// Determines whether the beginning of this <see cref="PathString"/> instance matches the specified <see cref="PathString"/> and returns
/// the matched and remaining segments.
/// </summary>
/// <param name="other">The <see cref="PathString"/> to compare.</param>
/// <param name="matched">The matched segments with the original casing in the source value.</param>
/// <param name="remaining">The remaining segments after the match.</param>
/// <returns>true if value matches the beginning of this string; otherwise, false.</returns>
public bool StartsWithSegments(PathString other, out PathString matched, out PathString remaining)
{
return StartsWithSegments(other, StringComparison.OrdinalIgnoreCase, out matched, out remaining);
}
/// <summary>
/// Determines whether the beginning of this <see cref="PathString"/> instance matches the specified <see cref="PathString"/> when compared
/// using the specified comparison option and returns the matched and remaining segments.
/// </summary>
/// <param name="other">The <see cref="PathString"/> to compare.</param>
/// <param name="comparisonType">One of the enumeration values that determines how this <see cref="PathString"/> and value are compared.</param>
/// <param name="matched">The matched segments with the original casing in the source value.</param>
/// <param name="remaining">The remaining segments after the match.</param>
/// <returns>true if value matches the beginning of this string; otherwise, false.</returns>
public bool StartsWithSegments(PathString other, StringComparison comparisonType, out PathString matched, out PathString remaining)
{
var value1 = Value ?? string.Empty;
var value2 = other.Value ?? string.Empty;
if (value1.StartsWith(value2, comparisonType))
{
if (value1.Length == value2.Length || value1[value2.Length] == '/')
{
matched = new PathString(value1.Substring(0, value2.Length));
remaining = new PathString(value1.Substring(value2.Length));
return true;
}
}
remaining = Empty;
matched = Empty;
return false;
}
/// <summary>
/// Adds two PathString instances into a combined PathString value.
/// </summary>
/// <returns>The combined PathString value</returns>
public PathString Add(PathString other)
{
if (HasValue &&
other.HasValue &&
Value[Value.Length - 1] == '/')
{
// If the path string has a trailing slash and the other string has a leading slash, we need
// to trim one of them.
return new PathString(Value + other.Value.Substring(1));
}
return new PathString(Value + other.Value);
}
/// <summary>
/// Combines a PathString and QueryString into the joined URI formatted string value.
/// </summary>
/// <returns>The joined URI formatted string value</returns>
public string Add(QueryString other)
{
return ToUriComponent() + other.ToUriComponent();
}
/// <summary>
/// Compares this PathString value to another value. The default comparison is StringComparison.OrdinalIgnoreCase.
/// </summary>
/// <param name="other">The second PathString for comparison.</param>
/// <returns>True if both PathString values are equal</returns>
public bool Equals(PathString other)
{
return Equals(other, StringComparison.OrdinalIgnoreCase);
}
/// <summary>
/// Compares this PathString value to another value using a specific StringComparison type
/// </summary>
/// <param name="other">The second PathString for comparison</param>
/// <param name="comparisonType">The StringComparison type to use</param>
/// <returns>True if both PathString values are equal</returns>
public bool Equals(PathString other, StringComparison comparisonType)
{
if (!HasValue && !other.HasValue)
{
return true;
}
return string.Equals(_value, other._value, comparisonType);
}
/// <summary>
/// Compares this PathString value to another value. The default comparison is StringComparison.OrdinalIgnoreCase.
/// </summary>
/// <param name="obj">The second PathString for comparison.</param>
/// <returns>True if both PathString values are equal</returns>
public override bool Equals(object obj)
{
if (ReferenceEquals(null, obj))
{
return !HasValue;
}
return obj is PathString && Equals((PathString)obj);
}
/// <summary>
/// Returns the hash code for the PathString value. The hash code is provided by the OrdinalIgnoreCase implementation.
/// </summary>
/// <returns>The hash code</returns>
public override int GetHashCode()
{
return (HasValue ? StringComparer.OrdinalIgnoreCase.GetHashCode(_value) : 0);
}
/// <summary>
/// Operator call through to Equals
/// </summary>
/// <param name="left">The left parameter</param>
/// <param name="right">The right parameter</param>
/// <returns>True if both PathString values are equal</returns>
public static bool operator ==(PathString left, PathString right)
{
return left.Equals(right);
}
/// <summary>
/// Operator call through to Equals
/// </summary>
/// <param name="left">The left parameter</param>
/// <param name="right">The right parameter</param>
/// <returns>True if both PathString values are not equal</returns>
public static bool operator !=(PathString left, PathString right)
{
return !left.Equals(right);
}
/// <summary>
/// </summary>
/// <param name="left">The left parameter</param>
/// <param name="right">The right parameter</param>
/// <returns>The ToString combination of both values</returns>
public static string operator +(string left, PathString right)
{
// This overload exists to prevent the implicit string<->PathString converter from
// trying to call the PathString+PathString operator for things that are not path strings.
return string.Concat(left, right.ToString());
}
/// <summary>
/// </summary>
/// <param name="left">The left parameter</param>
/// <param name="right">The right parameter</param>
/// <returns>The ToString combination of both values</returns>
public static string operator +(PathString left, string right)
{
// This overload exists to prevent the implicit string<->PathString converter from
// trying to call the PathString+PathString operator for things that are not path strings.
return string.Concat(left.ToString(), right);
}
/// <summary>
/// Operator call through to Add
/// </summary>
/// <param name="left">The left parameter</param>
/// <param name="right">The right parameter</param>
/// <returns>The PathString combination of both values</returns>
public static PathString operator +(PathString left, PathString right)
{
return left.Add(right);
}
/// <summary>
/// Operator call through to Add
/// </summary>
/// <param name="left">The left parameter</param>
/// <param name="right">The right parameter</param>
/// <returns>The PathString combination of both values</returns>
public static string operator +(PathString left, QueryString right)
{
return left.Add(right);
}
/// <summary>
/// Implicitly creates a new PathString from the given string.
/// </summary>
/// <param name="s"></param>
public static implicit operator PathString(string s)
=> ConvertFromString(s);
/// <summary>
/// Implicitly calls ToString().
/// </summary>
/// <param name="path"></param>
public static implicit operator string(PathString path)
=> path.ToString();
internal static PathString ConvertFromString(string s)
=> string.IsNullOrEmpty(s) ? new PathString(s) : FromUriComponent(s);
}
internal sealed class PathStringConverter : TypeConverter
{
public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
=> sourceType == typeof(string)
? true
: base.CanConvertFrom(context, sourceType);
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
=> value is string
? PathString.ConvertFromString((string)value)
: base.ConvertFrom(context, culture, value);
public override object ConvertTo(ITypeDescriptorContext context,
CultureInfo culture, object value, Type destinationType)
=> destinationType == typeof(string)
? value.ToString()
: base.ConvertTo(context, culture, value, destinationType);
}
}