This version produces JSON that is more compact and in my opinion more readable since you can see more at one time. It does this by formatting the deepest layer inline or like a compact array structure.
The code has no dependencies but is more complex.
{
"name":"Seller",
"schema":"dbo",
"CaptionFields":["Caption","Id"],
"fields":[
{"name":"Id","type":"Integer","length":"10","autoincrement":true,"nullable":false},
{"name":"FirstName","type":"Text","length":"50","autoincrement":false,"nullable":false},
{"name":"LastName","type":"Text","length":"50","autoincrement":false,"nullable":false},
{"name":"LotName","type":"Text","length":"50","autoincrement":false,"nullable":true},
{"name":"LotDetailsURL","type":"Text","length":"255","autoincrement":false,"nullable":true}
]
}
The code follows
private class IndentJsonInfo
{
public IndentJsonInfo(string prefix, char openingTag)
{
Prefix = prefix;
OpeningTag = openingTag;
Data = new List<string>();
}
public string Prefix;
public char OpeningTag;
public bool isOutputStarted;
public List<string> Data;
}
internal static string IndentJSON(string jsonString, int startIndent = 0, int indentSpaces = 2)
{
if (String.IsNullOrEmpty(jsonString))
return jsonString;
try
{
var jsonCache = new List<IndentJsonInfo>();
IndentJsonInfo currentItem = null;
var sbResult = new StringBuilder();
int curIndex = 0;
bool inQuotedText = false;
var chunk = new StringBuilder();
var saveChunk = new Action(() =>
{
if (chunk.Length == 0)
return;
if (currentItem == null)
throw new Exception("Invalid JSON: No container.");
currentItem.Data.Add(chunk.ToString());
chunk = new StringBuilder();
});
while (curIndex < jsonString.Length)
{
var cChar = jsonString[curIndex];
if (inQuotedText)
{
// Get the rest of quoted text.
chunk.Append(cChar);
// Determine if the quote is escaped.
bool isEscaped = false;
var excapeIndex = curIndex;
while (excapeIndex > 0 && jsonString[--excapeIndex] == '\\') isEscaped = !isEscaped;
if (cChar == '"' && !isEscaped)
inQuotedText = false;
}
else if (Char.IsWhiteSpace(cChar))
{
// Ignore all whitespace outside of quotes.
}
else
{
// Outside of Quotes.
switch (cChar)
{
case '"':
chunk.Append(cChar);
inQuotedText = true;
break;
case ',':
chunk.Append(cChar);
saveChunk();
break;
case '{':
case '[':
currentItem = new IndentJsonInfo(chunk.ToString(), cChar);
jsonCache.Add(currentItem);
chunk = new StringBuilder();
break;
case '}':
case ']':
saveChunk();
for (int i = 0; i < jsonCache.Count; i++)
{
var item = jsonCache[i];
var isLast = i == jsonCache.Count - 1;
if (!isLast)
{
if (!item.isOutputStarted)
{
sbResult.AppendLine(
"".PadLeft((startIndent + i) * indentSpaces) +
item.Prefix + item.OpeningTag);
item.isOutputStarted = true;
}
var newIndentString = "".PadLeft((startIndent + i + 1) * indentSpaces);
foreach (var listItem in item.Data)
{
sbResult.AppendLine(newIndentString + listItem);
}
item.Data = new List<string>();
}
else // If Last
{
if (!(
(item.OpeningTag == '{' && cChar == '}') ||
(item.OpeningTag == '[' && cChar == ']')
))
{
throw new Exception("Invalid JSON: Container Mismatch, Open '" + item.OpeningTag + "', Close '" + cChar + "'.");
}
string closing = null;
if (item.isOutputStarted)
{
var newIndentString = "".PadLeft((startIndent + i + 1) * indentSpaces);
foreach (var listItem in item.Data)
{
sbResult.AppendLine(newIndentString + listItem);
}
closing = cChar.ToString();
}
else
{
closing =
item.Prefix + item.OpeningTag +
String.Join("", currentItem.Data.ToArray()) +
cChar;
}
jsonCache.RemoveAt(i);
currentItem = (jsonCache.Count > 0) ? jsonCache[jsonCache.Count - 1] : null;
chunk.Append(closing);
}
}
break;
default:
chunk.Append(cChar);
break;
}
}
curIndex++;
}
if (inQuotedText)
throw new Exception("Invalid JSON: Incomplete Quote");
else if (jsonCache.Count != 0)
throw new Exception("Invalid JSON: Incomplete Structure");
else
{
if (chunk.Length > 0)
sbResult.AppendLine("".PadLeft(startIndent * indentSpaces) + chunk);
var result = sbResult.ToString();
return result;
}
}
catch (Exception ex)
{
throw; // Comment out to return unformatted text if the format failed.
// Invalid JSON, skip the formatting.
return jsonString;
}
}
The function allows you to specify a starting point for the indentation because I use this as part of a process that assembles very large JSON formatted backup files.
