/// <summary>
/// Extract the razor code fragment from a line of Javascript.
/// Input: A line of Javascript containing an @. The @ prefixes the razor code.
/// Note. the line may contain several fragments of razor.
/// The razor code is prefixed with @, it will probably be surrounded by quotes (single or double), but not always!
/// </summary>
public List<Fragment> Evaluate(string jsLine)
{
// we can't handle lines containing "@Url
if (jsLine.Contains("\"@Url")
|| jsLine.Contains("@{") )
{
throw new UnhandledPatternException(jsLine);
}
List<Fragment> output = new List<Fragment>();
// Multi fragment line?
if (jsLine.ToCharArray().Count(c => c == '@') > 1)
{
return ProcessMultiFragmentLine(jsLine);
}
Fragment fragment = new Fragment();
int atPosition = jsLine.IndexOf("@");
char firstCharacterToLeft = jsLine.Substring(atPosition - 1, 1).ToCharArray()[0]; // take character to the left
// Immediately Quoted?
// example: '@decommisionReason'
if (Constants.CharacterConstants.Quotes.Contains(firstCharacterToLeft)) // is a quote?
{
int rightDelimeterPos = GetRightDelimiterPosition(jsLine, atPosition, firstCharacterToLeft);
if (rightDelimeterPos > 0)
{
fragment.Text = jsLine.Substring(atPosition - 1, rightDelimeterPos - atPosition + 2); // include the quote delimiters
fragment.FragType = FragType.Quoted;
output.Add(fragment);
return output;
}
// We can't find the matching quote, or a space was hit before hitting the right quote
throw new UnhandledPatternException(jsLine);
}
// Non quoted?
// example: globalFunction = @Html.Raw(Newtonsoft.Json.JsonConvert.SerializeObject(Model.GlobalFunctionVmList));
if (firstCharacterToLeft == ' ')
{
// if there's a quote, play safe and terminate
if (jsLine.IndexOf("'", System.StringComparison.Ordinal) > 0)
{
throw new UnhandledPatternException(jsLine);
}
// Assume its unquoted, but terminated by a ;
int endDelimierPosition = jsLine.LastIndexOf(";");
if (endDelimierPosition == -1) // is there a ; ?
{
throw new UnhandledPatternException(jsLine);
}
fragment.Text = jsLine.Substring(atPosition, endDelimierPosition - atPosition); // don't include delimiters
fragment.FragType = FragType.Unquoted;
output.Add(fragment);
return output;
}
// Its not a pattern we are confident we recognize, it will have to be done manually
throw new UncaughtPatternException();
}
private List<Fragment> ProcessMultiFragmentLine(string jsline)
{
// I'm assuming the follow pattern of input
// data: "{'docId1':'" + '@ViewBag.docid' + "','conditionType1':'" + '@ViewBag.doctype' + "'}"
List<Fragment> result = new List<Fragment>();
int pos = 0;
foreach (char c in jsline) // scan the line char by char
{
if (c == '@')
{
string previousChar = jsline.Substring(pos - 1, 1);
if (previousChar == "'" || previousChar == "\"") // prefixed by quote ?
{
int endQuotePosition = GetEndQuotePosition(jsline, pos, previousChar);
Fragment fragment = new Fragment();
fragment.Text = jsline.Substring(pos - 1, endQuotePosition - pos + 2);
fragment.FragType = FragType.Quoted;
result.Add(fragment);
}
else
{
throw new UnhandledPatternException(jsline);
}
}
pos++;
}
return result;
}
