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Added MIME parsing
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@DavyWk
DavyWk committed Nov 29, 2014
1 parent 80305d0 commit 21782a3
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Showing 5 changed files with 182 additions and 232 deletions.
242 changes: 19 additions & 223 deletions MailParser.cs
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@@ -1,6 +1,7 @@
using System;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Globalization;
using System.Collections.Generic;

using Utils;
Expand All @@ -13,15 +14,15 @@ internal class MailParser
{
public POPMessage Message { get; private set; }

private List<string> lines;
private readonly List<string> lines;


public MailParser(List<string> messageLines)
{
lines = messageLines;
POPMessage m = new POPMessage();
var m = new POPMessage();
m.Raw = lines;

foreach(var l in lines)
{
// Just in case.
Expand All @@ -39,29 +40,27 @@ public MailParser(List<string> messageLines)
// Date MUST be in lowercase
else if(lowered.StartsWith("date:"))
m.ArrivalTime = GetDate(lowered);
else if(lowered.StartsWith("content-type:"))
m.CharSet = GetEncoding(trimmed);
else if(string.IsNullOrWhiteSpace(trimmed))
{
int currentLine = lines.IndexOf(l);
m.Header = lines.GetRange(0, currentLine);
break;
}
}


m.Body = new MimeParser(lines).GetBody();

// Some SMTP sever don't send all the fields.
m.Subject = MailParsingUtils.CompleteSubject(m.Subject);
if(m.CharSet == null)
m.CharSet = Encoding.UTF8;

if(m.ID == string.Empty)
m.ID = "NO ID";
if(m.Receivers == null)
{
m.Receivers = new List<Person>();
m.Receivers.Add(new Person("ERROR", "ERROR"));
}

m.Body = GetBody(m.CharSet);

m.ContainsHTML = CheckForHTML();

Message = m;
Expand All @@ -75,7 +74,7 @@ private static string GetID(string s)

private Person GetSender(string s)
{
Person p = new Person();
var p = new Person();
// In case there's something interesting on
// the following line.
int offset = lines.IndexOf(s); // "From:"
Expand Down Expand Up @@ -149,7 +148,7 @@ private List<Person> GetReceivers(string s)
index = 0;

// Handles multiple receivers.
var nextLine = lines[++offset];
string nextLine = lines[++offset];
int extraChars = MailDecoder.StartsWith(nextLine);
while(extraChars > 0)
{
Expand All @@ -169,7 +168,7 @@ private List<Person> GetReceivers(string s)

if((index = s.IndexOfAny(delimitor, index)) > -1)
{
Person receiver = new Person();
var receiver = new Person();
receiver.Name = s.SubstringEx('"', '"', index);

if(receiver.Name != string.Empty)
Expand Down Expand Up @@ -373,214 +372,11 @@ private static DateTime GetDate(string s)
return dt;
}

private Encoding GetEncoding(string s)
{ // Encoding.UTF8 is the default encoding.

string encoding;
int index = s.IndexOf("charset=") + 8; // 8: size of charset=

if(index == 0)
return Encoding.UTF8;

encoding = s.SubstringEx('"','"',index);

// In case there is no quotation marks.
if(encoding == string.Empty)
encoding = s.Substring(index, s.Length - index);

if(encoding.Contains(";"))
{
index = encoding.IndexOf(';');
encoding = encoding.Substring(0, index);
}

if(s.Contains("charset="))
return Encoding.GetEncoding(encoding);
else
return Encoding.UTF8;
}

private string GetBody(Encoding charset = null)
{
// "Compile-time constant".
if(charset == null)
charset = Encoding.UTF8;

var lBody = new List<string>();
var body = string.Empty;
int bodyStart = Int32.MaxValue;
int lastEmpty;

bool contentEncoded = false;
if(lines
.IndexOf("Content-Transfer-Encoding: base64") != -1)
contentEncoded = true;

if(contentEncoded)
{
bodyStart = lines.IndexOf(string.Empty) + 1;

while(lines[bodyStart].StartsWith("--") ||
lines[bodyStart + 1].StartsWith("--"))
{
bodyStart = lines.IndexOf(string.Empty, bodyStart) + 1;
}
lastEmpty = lines.IndexOf(string.Empty, bodyStart);
// lastEmpty counts ONLY if the next line
// is part of the MIME format.
if(!(lastEmpty != -1) && (lines[lastEmpty+1].StartsWith("--")))
lastEmpty = lines.Count;

lBody = lines.GetRange(bodyStart, lastEmpty - bodyStart);
string encodedBody = string.Join("", lBody.ToArray());
string decodedBody = charset.GetString(
Convert.FromBase64String(encodedBody));
string[] decodedArray = decodedBody.Split(
Environment.NewLine.ToCharArray(),
StringSplitOptions.RemoveEmptyEntries);

// Replaces the encoded ones with the decoded ones
lines.RemoveRange(bodyStart, lines.Count - bodyStart);
lines.InsertRange(bodyStart, decodedArray);
lBody = new List<string>(decodedArray);

return string.Join(string.Empty, lBody.ToArray());
}

int htmlBegin = -1;
int htmlEnd = -1;
for(int i = 0; i < lines.Count; i++)
{
string current = lines[i];

if((i > bodyStart) && current.StartsWith("Content-Type:")
&& (charset == Encoding.UTF8))
{
charset = GetEncoding(current);
}

if(i > bodyStart)
{
if((htmlBegin == -1)
&& (current.StartsWith("<html>") ||
current.StartsWithEx("<!DOCTYPE html")))
htmlBegin = i;

if((htmlEnd == -1) && current.StartsWith("</html>"))
{
htmlEnd = i;
break;
}

// Sometimes lines end with = sign.
if(current.EndsWith("="))
current = current.Remove(current.Length - 1 , 1);
current = MailDecoder.DecodeSpecialChars(current, charset);

// Just in case there is no HTML.
lBody.Add(current);

lines[i] = current;
// If bodyStart is already set, don't need to check again.
continue;
}

// Gets the first empty line (end of the headers).
if(string.IsNullOrWhiteSpace(current))
{
// Skips blank lines

int offset = i + 1;
while(string.IsNullOrWhiteSpace(lines[offset]))
offset++;

bodyStart = offset;
}
}

if((htmlBegin != -1) && (htmlBegin < htmlEnd))
{
lBody = lines.GetRange(htmlBegin, htmlEnd - htmlBegin);
}


// If there is no HTML.
if(lBody.Count == 0)
{
int emptyLine = 0;
foreach(var l in lines)
{
int currentOffset = lines.IndexOf(l);
if(emptyLine == 0)
{
if(string.IsNullOrWhiteSpace(l))
{
emptyLine = currentOffset + 1;
break;
}
}

if(currentOffset > emptyLine)
{
string current = lines[currentOffset];
// Sometimes lines end with = sign.
if(current.EndsWith("="))
current = current.Remove(current.Length - 1 , 1);
current = MailDecoder.DecodeSpecialChars(current,
Message.CharSet);
}
}

lBody = lines.GetRange(emptyLine, lines.Count - emptyLine);
}


body = string.Join(string.Empty, lBody.ToArray());

return body;
}

private bool CheckForHTML()
{
var kv = CheckForHtml();

if((kv.Key != -1) && (kv.Value != -1))
return true;
else
return false;
}

private KeyValuePair<int, int> CheckForHtml()
{
int begin = Int32.MaxValue;
int end = Int32.MaxValue;

for(int i = 0; i < lines.Count; i++)
{
if((end == Int32.MaxValue) && lines[i].StartsWith("<html>") ||
lines[i].StartsWithEx("<!DOCTYPE html"))
{
begin = i;
continue;
}

if((begin < i) && lines[i].StartsWith("</html"))
{
end = i;
break;
}
}

// Check for errors.
if((begin == Int32.MaxValue) || (end == Int32.MaxValue)
|| (begin > end))
{
begin = -1;
end = -1;
}

return new KeyValuePair<int, int>(begin, end);
}

private bool CheckForHTML()
{
return (from line in lines
where line.StartsWith("Content-Type: text/html;")
select line).Count<string>() > 0;
}
}
}

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