Encoding XPath Expressions with both single and double quotes

Question

XPath (v1) contains no way to encode expressions.

If you only have single OR double quotes then you can use expressions such as

//review[@name=\"Bob         


        

Answer 1

I was in need of this so I created this solution, for C#.

    /// <summary>
    /// Returns a valid XPath statement to use for searching attribute values regardless of 's or "s
    /// </summary>
    /// <param name="attributeValue">Attribute value to parse</param>
    /// <returns>Parsed attribute value in concat() if needed</returns>
    public static string GetXpathStringForAttributeValue(string attributeValue)
    {
        bool hasApos = attributeValue.Contains("'");
        bool hasQuote = attributeValue.Contains("\"");

        if (!hasApos)
        {
            return "'" + attributeValue + "'";
        }
        if (!hasQuote)
        {
            return "\"" + attributeValue + "\"";
        }

        StringBuilder result = new StringBuilder("concat(");
        StringBuilder currentArgument = new StringBuilder();
        for (int pos = 0; pos < attributeValue.Length; pos++)
        {
            switch (attributeValue[pos])
            {
                case '\'':
                    result.Append('\"');
                    result.Append(currentArgument.ToString());
                    result.Append("'\",");
                    currentArgument.Length = 0;
                    break;
                case '\"':
                    result.Append('\'');
                    result.Append(currentArgument.ToString());
                    result.Append("\"\',");
                    currentArgument.Length = 0;
                    break;
                default:
                    currentArgument.Append(attributeValue[pos]);
                    break;
            }
        }
        if (currentArgument.Length == 0)
        {
            result[result.Length - 1] = ')';
        }
        else
        {
            result.Append("'");
            result.Append(currentArgument.ToString());
            result.Append("')");
        }
        return result.ToString();
    }

Answer 2

Join in the fun

public string XPathLiteral(string text) {

    const string APOS = "'";
    const string QUOTE = @"""";

    int pos = 0;

    int posApos;
    int posQuote;

    posQuote = text.IndexOf(QUOTE, pos);

    if (posQuote < 0) {
        return QUOTE + text + QUOTE;
    }//if

    posApos = text.IndexOf(APOS, pos);

    if (posApos < 0) {
        return APOS + text + APOS;
    }//if

    bool containsApos = posApos < posQuote;

    StringBuilder sb = new StringBuilder("concat(", text.Length * 2);

    bool loop = true;
    bool comma = false;

    while (loop) {

        if (posApos < 0) {
            posApos = text.Length;
            loop = false;
        }//if

        if (posQuote < 0) {
            posQuote = text.Length;
            loop = false;
        }//if

        if (comma) {
            sb.Append(",");
        } else {
            comma = true;
        }//if

        if (containsApos) {
            sb.Append(QUOTE);
            sb.Append(text.Substring(pos, posQuote - pos));
            sb.Append(QUOTE);
            pos = posQuote;
            if (loop) posApos = text.IndexOf(APOS, pos + 1);
        } else {
            sb.Append(APOS);
            sb.Append(text.Substring(pos, posApos - pos));
            sb.Append(APOS);
            pos = posApos;
            if (loop) posQuote = text.IndexOf(QUOTE, pos + 1);
        }//if

        // Toggle
        containsApos = !containsApos;

    }//while

    sb.Append(")");

    return sb.ToString();

}//method