Jak obciąć string przed określonym słowem

Mam taki string:

{"data1":"value1","data2":"value2","data3":true,"data4":"value3"}ion: form-data; name="metadata" Content-Length: 83 Connection: Keep-Alive Accept-Encoding: gzip, deflate Accept Language: pl-PL,en,*User-Agent: Mozilla/5.0 Host: sec

W jaki sposób obciąć łańcuch przed ion: form-data, tak żeby wyszło:

{"data1":"value1","data2":"value2","data3":true,"data4":"value3"}

Wykorzystaj funkcje SysUtils.StrPos oraz System.Delete.

SetLength(strValue, Pos('}', strValue));

uses StrUtils 

var
Text : String;
i : Integer;
begin
  Text := '{"data1":"value1","data2":"value2","data3":true,"data4":"value3"}ion: form-data; name="metadata" Content-Length: 83 Connection: Keep-Alive Accept-Encoding: gzip, deflate Accept Language: pl-PL,en,*User-Agent: Mozilla/5.0 Host: sec';
  i := Length(Text);
  While (Text[i]<>'}') do Dec(i);
  Label1.Caption := LeftStr(Text,i);
end;