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Regex pattern for file extraction via url?

So, the html data I'm looking at is:
Action.log<br> 6/8/2015 3:45 PM
From this I need to extract either instances of Action.log,
My problem is I've been over a ton of regex tutorials and I still can't seem to brain up a pattern to extract it. I guess I'm lacking some fundamental understanding of regex, but any help would be appreciated.
Edit:
internal string[] ParseFolderIndex_Alpha(string url, WebDirectory directory)
{
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Timeout = 3 * 60 * 1000;
request.KeepAlive = true;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
List<string> fileLocations = new List<string>(); string line;
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
while ((line = reader.ReadLine()) != null)
{
int index = line.IndexOf("<a href=");
if (index >= 0)
{
string[] segments = line.Substring(index).Split('\"');
///Can Parse File Size Here: Add todo
if (!segments[1].Contains("/"))
{
fileLocations.Add(segments[1]);
UI.UpdatePatchNotes("Web File Found: " + segments[1]);
UI.UpdateProgressBar();
}
else
{
if (segments[1] != #"../")
{
directory.SubDirectories.Add(new WebDirectory(url + segments[1], this));
UI.UpdatePatchNotes("Web Directory Found: " + segments[1].Replace("/", string.Empty));
}
}
}
else if (line.Contains("</pre")) break;
}
}
response.Dispose(); /// After ((line = reader.ReadLine()) != null)
return fileLocations.ToArray<string>();
}
else return new string[0]; /// !(HttpStatusCode.OK)
}
catch (Exception e)
{
LogHandler.LogErrors(e.ToString(), this);
LogHandler.LogErrors(url, this);
return null;
}
}
That's what I was doing, the problem is I changed servers and the html IIS is displaying is different so I have to make new logic.
Edit / Conclusion:
First of all, I'm sorry I even mentions regex :P Secondly each platform will have to be handled individually depending on environment.
This is how I'm currently gathering the file names.
internal string[] ParseFolderIndex(string url, WebDirectory directory)
{
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Timeout = 3 * 60 * 1000;
request.KeepAlive = true;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
bool endMet = false;
if (response.StatusCode == HttpStatusCode.OK)
{
List<string> fileLocations = new List<string>(); string line;
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
while (!endMet)
{
line = reader.ReadLine();
if (line != null && line != "" && line.IndexOf("</A>") >= 0)
{
if (line.Contains("</html>")) endMet = true;
string[] segments = line.Replace("\\", "").Split('\"');
List<string> paths = new List<string>();
List<string> files = new List<string>();
for (int i = 0; i < segments.Length; i++)
{
if (!segments[i].Contains('<'))
paths.Add(segments[i]);
}
paths.RemoveAt(0);
foreach (String s in paths)
{
string[] secondarySegments = s.Split('/');
if (s.Contains(".") || s.Contains("Verinfo"))
files.Add(secondarySegments[secondarySegments.Length - 1]);
else
{
directory.SubDirectories.Add(new WebDirectory
(url + "/" + secondarySegments[secondarySegments.Length - 2], this));
UI.UpdatePatchNotes("Web Directory Found: " + secondarySegments[secondarySegments.Length - 2]);
}
}
foreach (String s in files)
{
if (!String.IsNullOrEmpty(s) && !s.Contains('%'))
{
fileLocations.Add(s);
UI.UpdatePatchNotes("Web File Found: " + s);
UI.UpdateProgressBar();
}
}
if (line.Contains("</pre")) break;
}
}
}
response.Dispose(); /// After ((line = reader.ReadLine()) != null)
return fileLocations.ToArray<string>();
}
else return new string[0]; /// !(HttpStatusCode.OK)
}
catch (Exception e)
{
LogHandler.LogErrors(e.ToString(), this);
LogHandler.LogErrors(url, this);
return null;
}
}

Regex for this is overkill.
It's too heavy, and considering the format of the string will always be the same, you're going to find it easier to debug and maintain using splitting and substrings.
class Program {
static void Main(string[] args) {
String s = "Action.log<br> 6/8/2015 3:45 PM ";
String[] t = s.Split('"');
String fileName = String.Empty;
//To get the entire file name and path....
fileName = t[1].Substring(0, (t[1].Length));
//To get just the file name (Action.log in this case)....
fileName = t[1].Substring(0, (t[1].Length)).Split('/').Last();
}
}

Try matching the following pattern:
<A HREF="(?<url>.*)">
Then get the group called url from the match results.
Working example: https://regex101.com/r/hW8iH6/1

string text = #"Action.log<br> 6/8/2015 3:45 PM";
var match = Regex.Match(text, #"^(.*).*$");
var result = match.Groups[1].Value;
Try http://regexr.com/ or Regexbuddy!

C# IO Stream not working like expected

I have this piece of code here:
private void button1_Click(object sender, EventArgs e)
{
StreamReader sr = new StreamReader("TextFile1.txt");
while ((line = sr.ReadLine()) != null)
{
if (line == textBox1.Text)
{
line = sr.ReadLine();
if (line == textBox2.Text)
{
MessageBox.Show("Logged in! Welcome " + textBox1.Text);
new Form2().Show();
this.Hide();
LoginSucces = true;
}
}
}
sr.Close();
if (LoginSucces == false) MessageBox.Show("Login Failed :(");
}
And it reads from this text:
AverageJavaGuy
Password
Chezzy
Password
The problem is that it doesnt work!
When I type in:
textBox1 = Chezzy.
textBox2 = Password.
it doesnt work...
it only works for AverageJavaGuy.
Does anyone know how to fix this?

Dictionary<string, string> userPass_dict = new Dictionary<string, string>(); // add this at class level
using (StreamReader sr = new StreamReader("TextFile1.txt"))
{
string line = "";
string line2 = "";
while (!sr.EndOfStream)
{
line = sr.ReadLine();
line2 = sr.ReadLine();
userPass_dict.Add(line, line2);
}
}

So it works for the first login/password, but not the second ?
Have you checked your textfile ?
Isn't the problem related to the dot beside "Chezzy" (in you post!) ?
Try to add "Console.WriteLine" or use debugger to fix your code and see what happens it the loop.
Also, I think the inner " sr.ReadLine();" in the loop may cause unexpected "shifting" according to the textfile content, use it carefully...

move line = sr.ReadLine(); to the outside the if statement

How to prevent adding an empty line to my file?

Im creating a text file and the last line is ""
private void lastRunDate()
{
String lastLine = readLastDate();
String[] date = lastLine.Split('/');
DateTime dt = new DateTime(Int32.Parse(date[2]), Int32.Parse(date[0]), Int32.Parse(date[1]));
DateTime currentDT = DateTime.Now;
argValue = 1;
if ((dt.Month == currentDT.Month) && (argValue == 0))
{
MessageBox.Show("This application has already been run this month");
this.Close();
}
}
private void AddRecordToFile()
{
DateTime now = DateTime.Now;
prepareToEmail();
string path = filepath;
bool dirtyData = true;
// This text is added only once to the file.
if (!File.Exists(path))
{
// Create a file to write to.
using (StreamWriter sw = File.CreateText(path))
{
sw.Write(now.ToShortDateString());
}
dirtyData = false;
}
if (dirtyData)
{
// This text is always added, making the file longer over time
// if it is not deleted.
using (StreamWriter sw = File.AppendText(path))
{
sw.Write(now.ToShortDateString());
}
}
}
private String readLastDate()
{
using (StreamReader sr = new StreamReader(filepath))
{
// Initialize to null so we are not stuck in loop forever in case there is nothing in the file to read
String line = null;
do
{
line = sr.ReadLine();
// Is this the end of the file?
if (line == null)
{
// Yes, so bail out of loop
return "01/01/1900"; // I had to put something
}
// Is the line empty?
if (line == String.Empty)
{
// Yes, so skip it
continue;
}
// Here you process the non-empty line
return line;
} while (true);
}
}
is what I am using to create the file (or append it)
now is a DateTime object
I used your (Karl) code to create a method called "readLastDate()"
I get the 1st date instead.

I'm probably being way to pragmatic and simple, but skip all the stream stuff and use File class directly like this...
string newLine = "";
if (!isFirstLine)
newLine = Environment.NewLine;
File.AppendAllText(
filePath,
string.Format("{0}{1}", newLine, DateTime.Now.ToString()));

You could use a sw.Write and PRE-pend a linefeed. Unfortunately that will give you an empty line at the start of the file.

Have you tried using the command .Trimend ('\n')?
http://msdn.microsoft.com/en-us/library/system.string.trimend.aspx

Do this:
sw.Write(now.ToShortDateString());
Here is the MSDN documentation for StreamWriter.WriteLine.
Here is the MSDN documentation for StreamWriter.Write.
UPDATE:
Keep using the WriteLine, but change the way you read your values in from the file:
using (StreamReader sr = new StreamReader(path))
{
// Initialize to null so we are not stuck in loop forever in case there is nothing in the file to read
String line = null;
do
{
line = sr.ReadLine();
// Is this the end of the file?
if (line == null)
{
// Yes, so bail out of loop
return;
}
// Is the line empty?
if (line == String.Empty)
{
// Yes, so skip it
continue;
}
// Here you process the non-empty line
} while (true);
}

Adding a record should be a simple matter of calling File.AppendAllText, as pointed out in another answer. Although I would recommend:
File.AppendAllText(filePath, DateTime.Now.ToString() + Environment.NewLine);
To read the last date from the file is also very easy:
string lastGoodLine = "01/01/1900";
using (StringReader sr = new StringReader(filePath))
{
while (!sr.EndOfStream)
{
string line = sr.ReadLine();
if (!string.IsNullOrEmpty(line))
lastGoodLine = line;
}
}
return lastGoodLine;

Filtering a line out of a string c#

I want to read a .txt file in c# and filter a line out of the string and only show that line. If the match is on the first line, i get a good output using streamreader.ReadLine. But if it's on the second line, i need to get it filtered. (i tought by creating a ReadLine loop?)
Thanks in advance
private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
{
StreamReader sr = new StreamReader(textBox1.Text);
string BoxLM1 = sr.ReadLine();
if (comboBox3.Text == "Anderlecht")
{
if (BoxLM1.Contains("Anderlecht"))
{
label5.Text = BoxLM1;
}
else
{
string BoxLM2 = sr.ReadToEnd();
MessageBox.Show(BoxLM2);
}

You can check all lines at once using File.ReadLines() method and LINQ:
var firstAnderlecht = File.ReadLines(textBox1.Text).FirstOrDefault(s => s.Contains("Anderlecht"));
if (firstAnderlecht != null) {
label5.Text = firstAnderlecht;
}
The ReadLines produces an enumerable of lines from the file; the FirstOrDefault method lets you apply a condition to all lines of the file without a loop, and pick the first line where the condition applies.

If you are manipulating big files i recommend to use this iterator:
private static IEnumerable FileIterator(String filePathe)
{
using (StreamReader streamReader = new StreamReader(filePathe))
{
String line;
while ((line = streamReader.ReadLine()) != null)
{
yield return line;
}
yield break;
}
}
it will prevent the loading of full file to RAM

Delete specific line from a text file?

I need to delete an exact line from a text file but I cannot for the life of me workout how to go about doing this.
Any suggestions or examples would be greatly appreciated?
Related Questions
Efficient way to delete a line from a text file (C#)

If the line you want to delete is based on the content of the line:
string line = null;
string line_to_delete = "the line i want to delete";
using (StreamReader reader = new StreamReader("C:\\input")) {
using (StreamWriter writer = new StreamWriter("C:\\output")) {
while ((line = reader.ReadLine()) != null) {
if (String.Compare(line, line_to_delete) == 0)
continue;
writer.WriteLine(line);
}
}
}
Or if it is based on line number:
string line = null;
int line_number = 0;
int line_to_delete = 12;
using (StreamReader reader = new StreamReader("C:\\input")) {
using (StreamWriter writer = new StreamWriter("C:\\output")) {
while ((line = reader.ReadLine()) != null) {
line_number++;
if (line_number == line_to_delete)
continue;
writer.WriteLine(line);
}
}
}

The best way to do this is to open the file in text mode, read each line with ReadLine(), and then write it to a new file with WriteLine(), skipping the one line you want to delete.
There is no generic delete-a-line-from-file function, as far as I know.

One way to do it if the file is not very big is to load all the lines into an array:
string[] lines = File.ReadAllLines("filename.txt");
string[] newLines = RemoveUnnecessaryLine(lines);
File.WriteAllLines("filename.txt", newLines);

Hope this simple and short code will help.
List linesList = File.ReadAllLines("myFile.txt").ToList();
linesList.RemoveAt(0);
File.WriteAllLines("myFile.txt"), linesList.ToArray());
OR use this
public void DeleteLinesFromFile(string strLineToDelete)
{
string strFilePath = "Provide the path of the text file";
string strSearchText = strLineToDelete;
string strOldText;
string n = "";
StreamReader sr = File.OpenText(strFilePath);
while ((strOldText = sr.ReadLine()) != null)
{
if (!strOldText.Contains(strSearchText))
{
n += strOldText + Environment.NewLine;
}
}
sr.Close();
File.WriteAllText(strFilePath, n);
}

You can actually use C# generics for this to make it real easy:
var file = new List<string>(System.IO.File.ReadAllLines("C:\\path"));
file.RemoveAt(12);
File.WriteAllLines("C:\\path", file.ToArray());

This can be done in three steps:
// 1. Read the content of the file
string[] readText = File.ReadAllLines(path);
// 2. Empty the file
File.WriteAllText(path, String.Empty);
// 3. Fill up again, but without the deleted line
using (StreamWriter writer = new StreamWriter(path))
{
foreach (string s in readText)
{
if (!s.Equals(lineToBeRemoved))
{
writer.WriteLine(s);
}
}
}

Read and remember each line
Identify the one you want to get rid
of
Forget that one
Write the rest back over the top of
the file

I cared about the file's original end line characters ("\n" or "\r\n") and wanted to maintain them in the output file (not overwrite them with what ever the current environment's char(s) are like the other answers appear to do). So I wrote my own method to read a line without removing the end line chars then used it in my DeleteLines method (I wanted the option to delete multiple lines, hence the use of a collection of line numbers to delete).
DeleteLines was implemented as a FileInfo extension and ReadLineKeepNewLineChars a StreamReader extension (but obviously you don't have to keep it that way).
public static class FileInfoExtensions
{
public static FileInfo DeleteLines(this FileInfo source, ICollection<int> lineNumbers, string targetFilePath)
{
var lineCount = 1;
using (var streamReader = new StreamReader(source.FullName))
{
using (var streamWriter = new StreamWriter(targetFilePath))
{
string line;
while ((line = streamReader.ReadLineKeepNewLineChars()) != null)
{
if (!lineNumbers.Contains(lineCount))
{
streamWriter.Write(line);
}
lineCount++;
}
}
}
return new FileInfo(targetFilePath);
}
}
public static class StreamReaderExtensions
{
private const char EndOfFile = '\uffff';
/// <summary>
/// Reads a line, similar to ReadLine method, but keeps any
/// new line characters (e.g. "\r\n" or "\n").
/// </summary>
public static string ReadLineKeepNewLineChars(this StreamReader source)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
char ch = (char)source.Read();
if (ch == EndOfFile)
return null;
var sb = new StringBuilder();
while (ch != EndOfFile)
{
sb.Append(ch);
if (ch == '\n')
break;
ch = (char)source.Read();
}
return sb.ToString();
}
}

Are you on a Unix operating system?
You can do this with the "sed" stream editor. Read the man page for "sed"

What?
Use file open, seek position then stream erase line using null.
Gotch it? Simple,stream,no array that eat memory,fast.
This work on vb.. Example search line culture=id where culture are namevalue and id are value and we want to change it to culture=en
Fileopen(1, "text.ini")
dim line as string
dim currentpos as long
while true
line = lineinput(1)
dim namevalue() as string = split(line, "=")
if namevalue(0) = "line name value that i want to edit" then
currentpos = seek(1)
fileclose()
dim fs as filestream("test.ini", filemode.open)
dim sw as streamwriter(fs)
fs.seek(currentpos, seekorigin.begin)
sw.write(null)
sw.write(namevalue + "=" + newvalue)
sw.close()
fs.close()
exit while
end if
msgbox("org ternate jua bisa, no line found")
end while
that's all..use #d