HttpUtility.ParseQueryString的可移植类库(PCL)版本

Question

是否有System.Web中包含的HttpUtility.ParseQueryString的可移植类库(PCL)版本或我可以使用的一些代码？我想读一个非常复杂的URL.

Answer 1

HttpUtility.ParseQueryString返回HttpValueCollection(内部类)继承自NameValueCollection.NameValueCollection是一个键值对的集合,如字典,但它支持重复,维护顺序和只实现IEnumerable(此集合是预先泛型).NameValueCollectionPCL不支持.

我的解决方案(部分解除并从.NET框架修改)是用HttpValueCollection替换Collection<HttpValue>where HttpValuekey只是一个键值对.

public sealed class HttpUtility
{
    public static HttpValueCollection ParseQueryString(string query)
    {
        if (query == null)
        {
            throw new ArgumentNullException("query");
        }

        if ((query.Length > 0) && (query[0] == '?'))
        {
            query = query.Substring(1);
        }

        return new HttpValueCollection(query, true);
    }
}

public sealed class HttpValue
{
    public HttpValue()
    {
    }

    public HttpValue(string key, string value)
    {
        this.Key = key;
        this.Value = value;
    }

    public string Key { get; set; }
    public string Value { get; set; }
}

public class HttpValueCollection : Collection<HttpValue>
{
    #region Constructors

    public HttpValueCollection()
    {
    }

    public HttpValueCollection(string query)
        : this(query, true)
    {
    }

    public HttpValueCollection(string query, bool urlencoded)
    {
        if (!string.IsNullOrEmpty(query))
        {
            this.FillFromString(query, urlencoded);
        }
    } 

    #endregion

    #region Parameters

    public string this[string key]
    {
        get { return this.First(x => string.Equals(x.Key, key, StringComparison.OrdinalIgnoreCase)).Value; }
        set { this.First(x => string.Equals(x.Key, key, StringComparison.OrdinalIgnoreCase)).Value = value; }
    }

    #endregion

    #region Public Methods

    public void Add(string key, string value)
    {
        this.Add(new HttpValue(key, value));
    }

    public bool ContainsKey(string key)
    {
        return this.Any(x => string.Equals(x.Key, key, StringComparison.OrdinalIgnoreCase));
    }

    public string[] GetValues(string key)
    {
        return this.Where(x => string.Equals(x.Key, key, StringComparison.OrdinalIgnoreCase)).Select(x => x.Value).ToArray();
    }

    public void Remove(string key)
    {
        this.Where(x => string.Equals(x.Key, key, StringComparison.OrdinalIgnoreCase))
            .ToList()
            .ForEach(x => this.Remove(x));
    }

    public override string ToString()
    {
        return this.ToString(true);
    }

    public virtual string ToString(bool urlencoded)
    {
        return this.ToString(urlencoded, null);
    }

    public virtual string ToString(bool urlencoded, IDictionary excludeKeys)
    {
        if (this.Count == 0)
        {
            return string.Empty;
        }

        StringBuilder stringBuilder = new StringBuilder();

        foreach (HttpValue item in this)
        {
            string key = item.Key;

            if ((excludeKeys == null) || !excludeKeys.Contains(key))
            {
                string value = item.Value;

                if (urlencoded)
                {
                    // If .NET 4.5 and above (Thanks @Paya)
                    key = WebUtility.UrlDecode(key);
                    // If .NET 4.0 use this instead.
                    // key = Uri.EscapeDataString(key);
                }

                if (stringBuilder.Length > 0)
                {
                    stringBuilder.Append('&');
                }

                stringBuilder.Append((key != null) ? (key + "=") : string.Empty);

                if ((value != null) && (value.Length > 0))
                {
                    if (urlencoded)
                    {
                        value = Uri.EscapeDataString(value);
                    }

                    stringBuilder.Append(value);
                }
            }
        }

        return stringBuilder.ToString();
    } 

    #endregion

    #region Private Methods

    private void FillFromString(string query, bool urlencoded)
    {
        int num = (query != null) ? query.Length : 0;
        for (int i = 0; i < num; i++)
        {
            int startIndex = i;
            int num4 = -1;
            while (i < num)
            {
                char ch = query[i];
                if (ch == '=')
                {
                    if (num4 < 0)
                    {
                        num4 = i;
                    }
                }
                else if (ch == '&')
                {
                    break;
                }
                i++;
            }
            string str = null;
            string str2 = null;
            if (num4 >= 0)
            {
                str = query.Substring(startIndex, num4 - startIndex);
                str2 = query.Substring(num4 + 1, (i - num4) - 1);
            }
            else
            {
                str2 = query.Substring(startIndex, i - startIndex);
            }

            if (urlencoded)
            {
                this.Add(Uri.UnescapeDataString(str), Uri.UnescapeDataString(str2));
            }
            else
            {
                this.Add(str, str2);
            }

            if ((i == (num - 1)) && (query[i] == '&'))
            {
                this.Add(null, string.Empty);
            }
        }
    } 

    #endregion
}

UPDATE

更新,以便HttpValueCollection现在继承自Collection而不是List,如注释中突出显示.

更新2

更新为使用WebUtility.UrlDecode,如果使用.NET 4.5,感谢@Paya.

Answer 2

您也可以像这样实现它:

public static class HttpUtility
{
    public static Dictionary<string, string> ParseQueryString(Uri uri)
    {
        var query = uri.Query.Substring(uri.Query.IndexOf('?') + 1); // +1 for skipping '?'
        var pairs = query.Split('&');
        return pairs
            .Select(o => o.Split('='))
            .Where(items => items.Count() == 2)
            .ToDictionary(pair => Uri.UnescapeDataString(pair[0]),
                pair => Uri.UnescapeDataString(pair[1]));
    }
}

这是一个单元测试:

public class HttpParseQueryValuesTests
{
    [TestCase("http://www.example.com", 0, "", "")]
    [TestCase("http://www.example.com?query=value", 1, "query", "value")]
    public void When_parsing_http_query_then_should_have_these_values(string uri, int expectedParamCount,
        string expectedKey, string expectedValue)
    {
        var queryParams = HttpUtility.ParseQueryString(new Uri(uri));
        queryParams.Count.Should().Be(expectedParamCount);

        if (queryParams.Count > 0)
            queryParams[expectedKey].Should().Be(expectedValue);
    }
}