转载
I have some JSON from a third party system that contains backslashes in the value. For example:
string extract = @"{""key"": ""\/Date(2015-02-02)\/""}";
which without the c# string escaping corresponds to the string:
{"key": "\/Date(2015-02-02)\/"}
I'd like to be able to format (e.g. indent) this JSON.
Typically for formatting, I might use something like JsonConvert like so:
JsonConvert.SerializeObject(JsonConvert.DeserializeObject(extract), Formatting.Indented)
This doesn't quite work, as it sees the value as a date, but as it's not in the standard MS format of /Date(ticks)/, it goes to a date of 1 Jan 1970:
"key": "1970-01-01T00:00:02.015+00:00"
Next approach is to use the serializer settings to not convert dates (I'm not bothered whether it recognises the field as a date, although it would probably be handy later on):
JsonSerializerSettings settings = new JsonSerializerSettings
DateParseHandling = DateParseHandling.None,
JsonConvert.SerializeObject(JsonConvert.DeserializeObject(extract, settings), Formatting.Indented);
This appears to have treated the backslash as an escape character during the deserialization, so it is "lost" once I see the final result:
"key": "/Date(2015-02-02)/"
Is there a way that I can format the JSON in C# (with or without JsonConvert), that will preserve the backslash in the value?
Note that the real JSON I am dealing with is (a) reasonably large, but not too large for some regex/find-replace solution, if really necessary (b) not under my control, so I can't change the format. I'm sure the answer is already on StackOverflow, but I'm finding it difficult to find the right search terms...
The basic problem is that, in a JSON string literal, the escaped solidus "/" means exactly the same as the unescaped solidus "/", and Json.NET parses and interprets this escaping at a very low level, namely JsonTextReader.ReadStringIntoBuffer(). Thus there's no way for higher level code to detect and remember whether a string literal was formatted as "/Date(2015-02-02)/" or "/Date(2015-02-02)/" and later write back one or the other as appropriate.
If you are OK with always adding the extra escaping to strings that start with /Date( and end with )/, you can use a custom subclass of JsonTextWriter to do this:
public class DateLiteralJsonTextWriter : JsonTextWriter
public DateLiteralJsonTextWriter(TextWriter writer) : base(writer) { }
public override void WriteValue(string value)
const string startToken = @"/Date(";
const string replacementStartToken = @"\/Date(";
const string endToken = @")/";
const string replacementEndToken = @")\/";
if (value != null && value.StartsWith(startToken) && value.EndsWith(endToken))
var sb = new StringBuilder();
// Add the initial quote.
sb.Append(QuoteChar);
// Add the new start token.
sb.Append(replacementStartToken);
// Add any necessary escaping to the innards of the "/Date(.*)/" string.
using (var writer = new StringWriter(sb))
using (var jsonWriter = new JsonTextWriter(writer) { StringEscapeHandling = this.StringEscapeHandling, Culture = this.Culture, QuoteChar = '\"' })
var content = value.Substring(startToken.Length, value.Length - startToken.Length - endToken.Length);
jsonWriter.WriteValue(content);
// Strip the embedded quotes from the above.
sb.Remove(replacementStartToken.Length + 1, 1);
sb.Remove(sb.Length - 1, 1);
// Add the replacement end token and final quote.
sb.Append(replacementEndToken);
sb.Append(QuoteChar);
// Write without any further escaping.
WriteRawValue(sb.ToString());
base.WriteValue(value);
var settings = new JsonSerializerSettings { DateParseHandling = DateParseHandling.None };
var sb = new StringBuilder();
using (var writer = new StringWriter(sb))
using (var jsonWriter = new DateLiteralJsonTextWriter(writer) { Formatting = Formatting.Indented})
JsonSerializer.CreateDefault(settings).Serialize(jsonWriter, JsonConvert.DeserializeObject(extract, settings));
Console.WriteLine(sb);
This prints:
