I need suggestion on getting a list of PDF files from the external storage in android device
1.You could traverse the folder and filter the PDF files:
public void Search_Pdf_Dir(File dir)
{
string pdfPattern = ".pdf";
File[] FileList = dir.ListFiles();
if (FileList != null)
{
for (int i = 0; i < FileList.Length; i++)
{
if (FileList[i].IsDirectory)
{
Search_Pdf_Dir(FileList[i]);
}
else
{
if (FileList[i].Name.EndsWith(pdfPattern))
{
//here you have that file.
}
}
}
}
}
then you could call like Search_Pdf_Dir(Android.OS.Environment.ExternalStorageDirectory);
2.use MediaStore - Uri to query all types of files :
ContentResolver cr = ContentResolver;
Android.Net.Uri uri = MediaStore.Files.GetContentUri("external");
// every column, although that is huge waste, you probably need
// BaseColumns.DATA (the path) only.
string[] projection = null;
string selectionMimeType = MediaStore.Files.FileColumns.MediaType + "=?";
string mimeType = MimeTypeMap.Singleton.GetMimeTypeFromExtension("pdf");
string[] selectionArgsPdf = new string[] { mimeType };
string sortOrder = null;
var allPdfFiles = cr.Query(uri, projection, selectionMimeType, selectionArgsPdf, sortOrder);
while (allPdfFiles.MoveToNext())
{
int column_index = allPdfFiles.GetColumnIndexOrThrow(MediaStore.Images.Media.InterfaceConsts.Data);
string filePath = allPdfFiles.GetString(column_index);//the pdf path
}
I Want to develope an app I give Url of a specific website to it,and it extract all links from that Web page. For each extracted link I want to get the HTML content. I am based in the concept of deep crawling.
My purpose is to get all email addresses of website. Below is my source code:
static string ExtractEmails(string data)
{
//instantiate with this pattern
Regex emailRegex = new Regex(#"\w+([-+.]\w+)*#\w+([-.]\w+)*\.\w+([-.]\w+)*", RegexOptions.IgnoreCase);
//find items that matches with our pattern
MatchCollection emailMatches = emailRegex.Matches(data);
//StringBuilder sb = new StringBuilder();
string s = "";
foreach (Match emailMatch in emailMatches)
{
//sb.AppendLine(emailMatch.Value);
s += emailMatch.Value + ",";
}
return s;
}
static readonly List<ParsResult> _results = new List<ParsResult>();
static Int32 _maxDepth = 4;
static String Foo(String urlToCheck = null, Int32 depth = 0, ParsResult parent = null)
{
string email = "";
if (depth >= _maxDepth) return email;
String html;
using (var wc = new WebClient())
html = wc.DownloadString(urlToCheck ?? parent.Url);
var doc = new HtmlDocument();
doc.LoadHtml(html);
var aNods = doc.DocumentNode.SelectNodes("//a");
if (aNods == null || !aNods.Any()) return email;
foreach (var aNode in aNods)
{
var url = aNode.Attributes["href"];
if (url == null)
continue;
var wc2 = new WebClient();
String html2 = wc2.DownloadString(url.Value);
email = ExtractEmails(html2);
Console.WriteLine(email);
var result = new ParsResult
{
Depth = depth,
Parent = parent,
Url = url.Value
};
_results.Add(result);
Console.WriteLine("{0} - {1}", depth, result.Url);
Foo(depth: depth + 1, parent: result);
return email;
}
return email;
}
static void Main(string[] args)
{
String res = Foo("http://www.mobileridoda.com", 0);
Console.WriteLine("emails " + res);
}
I want to dispaly in console all emails extracted by all pages of all links that are inside DOM of Main page, But it dispalys no emails in console. How can I solve this issue ?
Thank you
Found a few things wrong but no worries, got the details on why and what to do to fix them.
In your foreach loop, when you go through the first URL, you are using a return statement at the end essentially breaking the loop and terminating. Use return only after you have processed ALL the URLs and accumulated the email addresses.
You are overwriting the email (i see it as a csv) when you go over the loop. Use += to continue adding. email = ExtractEmails(html2);
You are not returning anything when you call Foo within your forEach loop. You need to use email += Foo(xyz). Foo(depth: depth + 1, parent: result);
You are going through a URL that you have already processed... possibly causing an infinite cycle. I added a list of strings that keeps track of URLs you have already visited so as to prevent the infinite loop you might get into.
Here is a complete working solution.
static string ExtractEmails(string data)
{
//instantiate with this pattern
Regex emailRegex = new Regex(#"\w+([-+.]\w+)*#\w+([-.]\w+)*\.\w+([-.]\w+)*", RegexOptions.IgnoreCase);
//find items that matches with our pattern
MatchCollection emailMatches = emailRegex.Matches(data);
//StringBuilder sb = new StringBuilder();
string s = "";
foreach (Match emailMatch in emailMatches)
{
//sb.AppendLine(emailMatch.Value);
s += emailMatch.Value + ",";
}
return s;
}
static readonly List<ParsResult> _results = new List<ParsResult>();
static Int32 _maxDepth = 4;
static List<string> urlsAlreadyVisited = new List<string>();
static String Foo(String urlToCheck = null, Int32 depth = 0, ParsResult parent = null)
{
if (urlsAlreadyVisited.Contains(urlToCheck))
return string.Empty;
else
urlsAlreadyVisited.Add(urlToCheck);
string email = "";
if (depth >= _maxDepth) return email;
String html;
using (var wc = new WebClient())
html = wc.DownloadString(urlToCheck ?? parent.Url);
var doc = new HtmlDocument();
doc.LoadHtml(html);
var aNods = doc.DocumentNode.SelectNodes("//a");
if (aNods == null || !aNods.Any()) return email;
// Get Distinct URLs from all the URls on this page.
List<string> allUrls = aNods.ToList().Select(x => x.Attributes["href"].Value).Where(url => url.StartsWith("http")).Distinct().ToList();
foreach (string url in allUrls)
{
var wc2 = new WebClient();
try
{
email += ExtractEmails(wc2.DownloadString(url));
}
catch { /* Swallow Exception ... URL not found or other errors. */ continue; }
Console.WriteLine(email);
var result = new ParsResult
{
Depth = depth,
Parent = parent,
Url = url
};
_results.Add(result);
Console.WriteLine("{0} - {1}", depth, result.Url);
email += Foo(depth: depth + 1, parent: result);
}
return email;
}
public class ParsResult
{
public int Depth { get; set; }
public ParsResult Parent { get; set; }
public string Url { get; set; }
}
// ========== MAIN CLASS ==========
static void Main(string[] args)
{
String res = Foo("http://www.mobileridoda.com", 0);
Console.WriteLine("emails " + res);
}
I have a method which unzips file from my method, and I have a separate method which I want to create so it can read the unzip files and load them as needed.
private string UnzipFiles()
{
Chilkat.Zip zip = new Chilkat.Zip();
string zippedFilePath = #"C:\Users\TestData";
string unzippedFilePath = #"C:\Users\Temp";
bool success = zip.UnlockComponent("LIVECOZIP_3BzssvnbmYxp");
if (!success)
{
string errorMsg = zip.LastErrorText;
Console.WriteLine(errorMsg);
return errorMsg;
}
string[] newzip = (Directory.GetFiles(zippedFilePath));
foreach (string file in newzip)
{
success = zip.OpenZip(file);
{
Console.WriteLine(zip.LastErrorText);
}
zip.DecryptPassword = "hANhvU8MX7iq0f2M";
int unzipCount;
unzipCount = zip.Unzip(unzippedFilePath);
if (unzipCount < 0)
{
Console.WriteLine("unzipping file");
}
}
return unzippedFilePath;
The method below is where I need help. I want to call the method above and be able to read each file. Right now I am getting error.
public void LoadNewFile()
{
UnzipFiles();
foreach (String file in UnzipFiles)
//How to call each file?
{
userSelectedFilePath += file + Environment.NewLine;
names_of_files.Add(file);
}
Try this:
var path = UnzipFiles();
var unZippedFiles = Directory.GetFiles(path);
foreach (var file in unZippedFiles)
{
//tratata
}
I would say you need to change UnzipFiles to return a List of strings. Something like this:
private List<string> UnzipFiles()
{
Chilkat.Zip zip = new Chilkat.Zip();
string zippedFilePath = #"C:\Users\TestData";
string unzippedFilePath = #"C:\Users\Temp";
var unzippedFileList = new List<string>();
bool success = zip.UnlockComponent("LIVECOZIP_3BzssvnbmYxp");
if (!success)
{
string errorMsg = zip.LastErrorText;
Console.WriteLine(errorMsg);
return errorMsg;
}
string[] newzip = (Directory.GetFiles(zippedFilePath));
foreach (string file in newzip)
{
unzippedFileList.Add(file);
success = zip.OpenZip(file);
{
Console.WriteLine(zip.LastErrorText);
}
zip.DecryptPassword = "hANhvU8MX7iq0f2M";
int unzipCount;
unzipCount = zip.Unzip(unzippedFilePath);
if (unzipCount < 0)
{
Console.WriteLine("unzipping file");
}
}
return unzippedFileList;
}
The exception is happen most of the times but there are times it's working fine.
The exception is always the same
The remote server returned an error: (500) Internal Server Error.
Also the stacktrace is the same:
at System.Net.WebClient.DownloadDataInternal(Uri address, WebRequest& request)
at System.Net.WebClient.DownloadData(Uri address)
at System.Net.WebClient.DownloadData(String address)
at SatelliteImages.ExtractImages.ExtractDateAndTime(String baseAddress) in D:\C-Sharp\SatelliteImages\SatelliteImages\SatelliteImages\ExtractImages.cs:line 120
Line 120 is:
var temp = wc.DownloadData("/en");
The method:
public void ExtractDateAndTime(string baseAddress)
{
try
{
var wc = new WebClient();
wc.BaseAddress = baseAddress;
HtmlDocument doc = new HtmlDocument();
var temp = wc.DownloadData("/en");
doc.Load(new MemoryStream(temp));
var secTokenScript = doc.DocumentNode.Descendants()
.Where(e =>
String.Compare(e.Name, "script", true) == 0 &&
String.Compare(e.ParentNode.Name, "div", true) == 0 &&
e.InnerText.Length > 0 &&
e.InnerText.Trim().StartsWith("var region")
).FirstOrDefault().InnerText;
var securityToken = secTokenScript;
securityToken = securityToken.Substring(0, securityToken.IndexOf("arrayImageTimes.push"));
securityToken = secTokenScript.Substring(securityToken.Length).Replace("arrayImageTimes.push('", "").Replace("')", "");
var dates = securityToken.Trim().Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
var scriptDates = dates.Select(x => new ScriptDate { DateString = x });
foreach (var date in scriptDates)
{
DatesAndTimes.Add(date.DateString);
}
}
catch(WebException wex)
{
if (wex.Response != null)
{
using (var errorResponse = (HttpWebResponse)wex.Response)
{
using (var reader = new StreamReader(errorResponse.GetResponseStream()))
{
string error = reader.ReadToEnd();
}
}
}
countriescodes = new List<string>();
countriesnames = new List<string>();
DatesAndTimes = new List<string>();
imagesUrls = new List<string>();
this.Init();
}
}
When I use a breakpoint on the line:
string error = reader.ReadToEnd();
I see html content and in the content I see the text:
error occurred while processing your request. Return to the homepage of Sat24.com
What I want to do is somehow when the exception happen to start over again and try the download try the method ExtractDateAndTime.
I think using a timer some how and count back showing the user something like 30 seconds and try again. Will 30 seconds try will be consider as spam/flooding in the server site ?
This is the full class code but the exception is on this method ExtractDateAndTime.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Net;
using System.Xml;
using HtmlAgilityPack;
using System.ComponentModel;
namespace SatelliteImages
{
class ExtractImages
{
static WebClient client;
static string htmltoextract;
public static List<string> countriescodes = new List<string>();
public static List<string> countriesnames = new List<string>();
public static List<string> DatesAndTimes = new List<string>();
public static List<string> imagesUrls = new List<string>();
static string firstUrlPart = "http://www.sat24.com/image2.ashx?region=";
static string secondUrlPart = "&time=";
static string thirdUrlPart = "&ir=";
public class ProgressEventArgs : EventArgs
{
public int Percentage { get; set; }
public string StateText { get; set; }
}
public event EventHandler<ProgressEventArgs> ProgressChanged;
public void Init()
{
object obj = null;
int index = 0;
ExtractCountires();
foreach (string cc in countriescodes)
{
// raise event here
ProgressChanged?.Invoke(obj,new ProgressEventArgs{ Percentage = 100 * index / countriescodes.Count, StateText = cc });
ExtractDateAndTime("http://www.sat24.com/image2.ashx?region=" + cc);
index +=1;
}
ImagesLinks();
}
public void ExtractCountires()
{
try
{
htmltoextract = "http://sat24.com/en/?ir=true";//"http://sat24.com/en/";// + regions;
client = new WebClient();
client.DownloadFile(htmltoextract, #"c:\temp\sat24.html");
client.Dispose();
string tag1 = "<li><a href=\"/en/";
string tag2 = "</a></li>";
string s = System.IO.File.ReadAllText(#"c:\temp\sat24.html");
s = s.Substring(s.IndexOf(tag1));
s = s.Substring(0, s.LastIndexOf(tag2) + tag2.ToCharArray().Length);
s = s.Replace("\r", "").Replace("\n", "").Replace(" ", "");
string[] parts = s.Split(new string[] { tag1, tag2 }, StringSplitOptions.RemoveEmptyEntries);
string tag3 = "<li><ahref=\"/en/";
for (int i = 0; i < parts.Length; i++)
{
if (i == 17)
{
//break;
}
string l = "";
if (parts[i].Contains(tag3))
l = parts[i].Replace(tag3, "");
string z1 = l.Substring(0, l.IndexOf('"'));
if (z1.Contains("</ul></li><liclass="))
{
z1 = z1.Replace("</ul></li><liclass=", "af");
}
countriescodes.Add(z1);
countriescodes.GroupBy(n => n).Any(c => c.Count() > 1);
string z2 = parts[i].Substring(parts[i].LastIndexOf('>') + 1);
if (z2.Contains("&"))
{
z2 = z2.Replace("&", " & ");
}
countriesnames.Add(z2);
countriesnames.GroupBy(n => n).Any(c => c.Count() > 1);
}
}
catch (Exception e)
{
if (countriescodes.Count == 0)
{
countriescodes = new List<string>();
countriesnames = new List<string>();
DatesAndTimes = new List<string>();
imagesUrls = new List<string>();
Init();
}
}
}
public void ExtractDateAndTime(string baseAddress)
{
try
{
var wc = new WebClient();
wc.BaseAddress = baseAddress;
HtmlDocument doc = new HtmlDocument();
var temp = wc.DownloadData("/en");
doc.Load(new MemoryStream(temp));
var secTokenScript = doc.DocumentNode.Descendants()
.Where(e =>
String.Compare(e.Name, "script", true) == 0 &&
String.Compare(e.ParentNode.Name, "div", true) == 0 &&
e.InnerText.Length > 0 &&
e.InnerText.Trim().StartsWith("var region")
).FirstOrDefault().InnerText;
var securityToken = secTokenScript;
securityToken = securityToken.Substring(0, securityToken.IndexOf("arrayImageTimes.push"));
securityToken = secTokenScript.Substring(securityToken.Length).Replace("arrayImageTimes.push('", "").Replace("')", "");
var dates = securityToken.Trim().Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
var scriptDates = dates.Select(x => new ScriptDate { DateString = x });
foreach (var date in scriptDates)
{
DatesAndTimes.Add(date.DateString);
}
}
catch(WebException wex)
{
if (wex.Response != null)
{
using (var errorResponse = (HttpWebResponse)wex.Response)
{
using (var reader = new StreamReader(errorResponse.GetResponseStream()))
{
string error = reader.ReadToEnd();
}
}
}
countriescodes = new List<string>();
countriesnames = new List<string>();
DatesAndTimes = new List<string>();
imagesUrls = new List<string>();
this.Init();
}
}
public class ScriptDate
{
public string DateString { get; set; }
public int Year
{
get
{
return Convert.ToInt32(this.DateString.Substring(0, 4));
}
}
public int Month
{
get
{
return Convert.ToInt32(this.DateString.Substring(4, 2));
}
}
public int Day
{
get
{
return Convert.ToInt32(this.DateString.Substring(6, 2));
}
}
public int Hours
{
get
{
return Convert.ToInt32(this.DateString.Substring(8, 2));
}
}
public int Minutes
{
get
{
return Convert.ToInt32(this.DateString.Substring(10, 2));
}
}
}
public void ImagesLinks()
{
int cnt = 0;
foreach (string countryCode in countriescodes)
{
cnt++;
for (; cnt < DatesAndTimes.Count(); cnt++)
{
string imageUrl = firstUrlPart + countryCode + secondUrlPart + DatesAndTimes[cnt] + thirdUrlPart + "true";
imagesUrls.Add(imageUrl);
if (cnt % 10 == 0) break;
}
}
}
}
}
What i want is in case of the exception happen to start over clean over again the whole class operation.
In Form1 i start the class operation first time once:
In top:
ExtractImages ei = new ExtractImages();
Then in constructor:
ei.Init();
The problem is this exception that sometimes happen.
You could go with something like Polly or the Transient Fault Handling Application Block to apply a retry strategy to your code.
Both packages provide multiple out-of-the-box components for various scenarios and you can always develop you own. Some of the included retry policies:
Incremental
Fixed interval
Exponential back-off
Retry
Retry for ever
Retry and wait
Wait and retry for ever
...
How to remove a query string by Key from a Url?
I have the below method which works fine but just wondering is there any better/shorter way? or a built-in .NET method which can do it more efficiently?
public static string RemoveQueryStringByKey(string url, string key)
{
var indexOfQuestionMark = url.IndexOf("?");
if (indexOfQuestionMark == -1)
{
return url;
}
var result = url.Substring(0, indexOfQuestionMark);
var queryStrings = url.Substring(indexOfQuestionMark + 1);
var queryStringParts = queryStrings.Split(new [] {'&'});
var isFirstAdded = false;
for (int index = 0; index <queryStringParts.Length; index++)
{
var keyValue = queryStringParts[index].Split(new char[] { '=' });
if (keyValue[0] == key)
{
continue;
}
if (!isFirstAdded)
{
result += "?";
isFirstAdded = true;
}
else
{
result += "&";
}
result += queryStringParts[index];
}
return result;
}
For example I can call it like:
Console.WriteLine(RemoveQueryStringByKey(#"http://www.domain.com/uk_pa/PostDetail.aspx?hello=hi&xpid=4578", "xpid"));
Hope the question is clear.
Thanks,
This works well:
public static string RemoveQueryStringByKey(string url, string key)
{
var uri = new Uri(url);
// this gets all the query string key value pairs as a collection
var newQueryString = HttpUtility.ParseQueryString(uri.Query);
// this removes the key if exists
newQueryString.Remove(key);
// this gets the page path from root without QueryString
string pagePathWithoutQueryString = uri.GetLeftPart(UriPartial.Path);
return newQueryString.Count > 0
? String.Format("{0}?{1}", pagePathWithoutQueryString, newQueryString)
: pagePathWithoutQueryString;
}
an example:
RemoveQueryStringByKey("https://www.google.co.uk/search?#hl=en&output=search&sclient=psy-ab&q=cookie", "q");
and returns:
https://www.google.co.uk/search?#hl=en&output=search&sclient=psy-ab
var queryString = "hello=hi&xpid=4578";
var qs = System.Web.HttpUtility.ParseQueryString(queryString);
qs.Remove("xpid");
var newQuerystring = qs.ToString();
This still works in .NET 5.
There's a useful class called UriBuilder in the System namespace. We can use it along with a couple of extension methods to do the following:
Uri u = new Uri("http://example.com?key1=value1&key2=value2");
u = u.DropQueryItem("key1");
Or like this:
Uri u = new Uri("http://example.com?key1=value1&key2=value2");
UriBuilder b = new UriBuilder(u);
b.RemoveQueryItem("key1");
u = b.Uri;
The extension methods:
using System;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
public static class UriExtensions
{
public static Uri DropQueryItem(this Uri u, string key)
{
UriBuilder b = new UriBuilder(u);
b.RemoveQueryItem(key);
return b.Uri;
}
}
public static class UriBuilderExtensions
{
private static string _ParseQueryPattern = #"(?<key>[^&=]+)={0,1}(?<value>[^&]*)";
private static Regex _ParseQueryRegex = null;
private static Regex ParseQueryRegex
{
get
{
if (_ParseQueryRegex == null)
{
_ParseQueryRegex = new Regex(_ParseQueryPattern, RegexOptions.Compiled | RegexOptions.Singleline);
}
return _ParseQueryRegex;
}
}
public static void SetQueryItem(this UriBuilder b, string key, string value)
{
NameValueCollection parms = ParseQueryString(b.Query);
parms[key] = value;
b.Query = RenderQuery(parms);
}
public static void RemoveQueryItem(this UriBuilder b, string key)
{
NameValueCollection parms = ParseQueryString(b.Query);
parms.Remove(key);
b.Query = RenderQuery(parms);
}
private static string RenderQuery(NameValueCollection parms)
{
StringBuilder sb = new StringBuilder();
for (int i=0; i<parms.Count; i++)
{
string key = parms.Keys[i];
sb.Append(key + "=" + parms[key]);
if (i < parms.Count - 1)
{
sb.Append("&");
}
}
return sb.ToString();
}
public static NameValueCollection ParseQueryString(string query, bool caseSensitive = true)
{
NameValueCollection pairs = new NameValueCollection(caseSensitive ? StringComparer.Ordinal : StringComparer.OrdinalIgnoreCase);
string q = query.Trim().TrimStart(new char[] {'?'});
MatchCollection matches = ParseQueryRegex.Matches(q);
foreach (Match m in matches)
{
string key = m.Groups["key"].Value;
string value = m.Groups["value"].Value;
if (pairs[key] != null)
{
pairs[key] = pairs[key] + "," + value;
}
else
{
pairs[key] = value;
}
}
return pairs;
}
}
I know this is a rather old question, but everything I read felt a bit complicated.
public Uri GetUriWithoutQueryParam( Uri originalUri, string paramKey ) {
NameValueCollection newQuery = HttpUtility.ParseQueryString( originalUri.Query );
newQuery.Remove( paramKey );
return new UriBuilder( originalUri ) { Query = newQuery.ToString() }.Uri;
}
We can also do it using regex
string queryString = "Default.aspx?Agent=10&Language=2"; //Request.QueryString.ToString();
string parameterToRemove="Language"; //parameter which we want to remove
string regex=string.Format("(&{0}=[^&\s]+|(?<=\?){0}=[^&\s]+&?)",parameterToRemove); //this will not work for javascript, for javascript you can do following
string finalQS = Regex.Replace(queryString, regex, "");
//javascript(following is not js syntex, just want to give idea how we can able do it in js)
string regex1 = string.Format("(&{0}=[^&\s]+)",parameterToRemove);
string regex2 = string.Format("(\?{0}=[^&\s]+&?)",parameterToRemove);
string finalQS = Regex.Replace(queryString, regex1, "").Replace(queryString, regex2, "");
https://regexr.com/3i9vj
How about this:
string RemoveQueryStringByKey(string url, string key)
{
string ret = string.Empty;
int index = url.IndexOf(key);
if (index > -1)
{
string post = string.Empty;
// Find end of key's value
int endIndex = url.IndexOf('&', index);
if (endIndex != -1) // Last query string value?
{
post = url.Substring(endIndex, url.Length - endIndex);
}
// Decrement for ? or & character
--index;
ret = url.Substring(0, index) + post;
}
return ret;
}
I found a way without using Regex:
private string RemoveQueryStringByKey(string sURL, string sKey) {
string sOutput = string.Empty;
int iQuestion = sURL.IndexOf('?');
if (iQuestion == -1) return (sURL);
int iKey = sURL.Substring(iQuestion).IndexOf(sKey) + iQuestion;
if (iKey == -1) return (sURL);
int iNextAnd = sURL.Substring(iKey).IndexOf('&') + iKey + 1;
if (iNextAnd == -1) {
sOutput = sURL.Substring(0, iKey - 1);
}
else {
sOutput = sURL.Remove(iKey, iNextAnd - iKey);
}
return (sOutput);
}
I did try this with adding another field at the end, and it works fine for that too.
I'm thinking the shortest way (that I believe produces a valid URL in all cases, assuming the URL was valid to begin with) would be to use this regex (where getRidOf is the variable name you are trying to remove) and the replacement is a zero-length string ""):
(?<=[?&])getRidOf=[^&]*(&|$)
or maybe even
\bgetRidOf=[^&]*(&|$)
while possibly not the absolute prettiest URLs, I think they are all valid:
INPUT OUTPUT
----------- ------------
blah.com/blah.php?getRidOf=d.co&blah=foo blah.com/blah.php?blah=foo
blah.com/blah.php?f=0&getRidOf=d.co&blah=foo blah.com/blah.php?f=0&blah=foo
blah.com/blah.php?hello=true&getRidOf=d.co blah.com/blah.php?hello=true&
blah.com/blah.php?getRidOf=d.co blah.com/blah.php?
and it's a simple regex replace:
Dim RegexObj as Regex = New Regex("(?<=[?&])getRidOf=[^&]*(&|$)")
RegexObj.Replace("source.url.com/find.htm?replace=true&getRidOf=PLEASE!!!", "")
...should result in the string:
"source.url.com/find.htm?replace=true&"
...which seems to be valid for an ASP.Net application, while replace does equal true (not true& or anything like that)
I'll try to adapt it if you have a case where it won't work :)
public static string RemoveQueryStringByKey(string sURL, string sKey)
{
string sOutput = string.Empty;
string sToReplace = string.Empty;
int iFindTheKey = sURL.IndexOf(sKey);
if (iFindTheKey == -1) return (sURL);
int iQuestion = sURL.IndexOf('?');
if (iQuestion == -1) return (sURL);
string sEverythingBehindQ = sURL.Substring(iQuestion);
List<string> everythingBehindQ = new List<string>(sEverythingBehindQ.Split('&'));
foreach (string OneParamPair in everythingBehindQ)
{
int iIsKeyInThisParamPair = OneParamPair.IndexOf(sKey);
if (iIsKeyInThisParamPair != -1)
{
sToReplace = "&" + OneParamPair;
}
}
sOutput = sURL.Replace(sToReplace, "");
return (sOutput);
}
Below code before deleting your QueryString.
PropertyInfo isreadonly =
typeof(System.Collections.Specialized.NameValueCollection).GetProperty(
"IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
// make collection editable
isreadonly.SetValue(this.Request.QueryString, false, null);
// remove
this.Request.QueryString.Remove("yourKey");
Sorry this is a bit dirty but should work in older framework
public String RemoveQueryString( String rawUrl , String keyName)
{
var currentURL_Split = rawUrl.Split('&').ToList();
currentURL_Split = currentURL_Split.Where(o => !o.ToLower().StartsWith(keyName.ToLower()+"=")).ToList();
String New_RemovedKey = String.Join("&", currentURL_Split.ToArray());
New_RemovedKey = New_RemovedKey.Replace("&&", "&");
return New_RemovedKey;
}
Here is my solution:
I'v added some extra input validation.
public static void TryRemoveQueryStringByKey(ref string url, string key)
{
if (string.IsNullOrEmpty(url) ||
string.IsNullOrEmpty(key) ||
Uri.IsWellFormedUriString(url, UriKind.RelativeOrAbsolute) == false)
{
return false;
}
try
{
Uri uri = new Uri(url);
// This gets all the query string key value pairs as a collection
NameValueCollection queryCollection = HttpUtility.ParseQueryString(uri.Query);
string keyValue = queryCollection.Get(key);
if (url.IndexOf("&" + key + "=" + keyValue, StringComparison.OrdinalIgnoreCase) >= 0)
{
url = url.Replace("&" + key + "=" + keyValue, String.Empty);
return true;
}
else if (url.IndexOf("?" + key + "=" + keyValue, StringComparison.OrdinalIgnoreCase) >= 0)
{
url = url.Replace("?" + key + "=" + keyValue, String.Empty);
return true;
}
else
{
return false;
}
}
catch
{
return false;
}
}
Some unit testing examples:
string url1 = "http://www.gmail.com?a=1&cookie=cookieValue"
Assert.IsTrue(TryRemoveQueryStringByKey(ref url1,"cookie")); //OUTPUT: "http://www.gmail.com?a=1"
string url2 = "http://www.gmail.com?cookie=cookieValue"
Assert.IsTrue(TryRemoveQueryStringByKey(ref url2,"cookie")); //OUTPUT: "http://www.gmail.com"
string url3 = "http://www.gmail.com?cookie="
Assert.IsTrue(TryRemoveQueryStringByKey(ref url2,"cookie")); //OUTPUT: "http://www.gmail.com"
Here's a full solution that works with >= 0 params specified, and any form of URL:
/// <summary>
/// Given a URL in any format, return URL with specified query string param removed if it exists
/// </summary>
public static string StripQueryStringParam(string url, string paramToRemove)
{
return StripQueryStringParams(url, new List<string> {paramToRemove});
}
/// <summary>
/// Given a URL in any format, return URL with specified query string params removed if it exists
/// </summary>
public static string StripQueryStringParams(string url, List<string> paramsToRemove)
{
if (paramsToRemove == null || !paramsToRemove.Any()) return url;
var splitUrl = url.Split('?');
if (splitUrl.Length == 1) return url;
var urlFirstPart = splitUrl[0];
var urlSecondPart = splitUrl[1];
// Even though in most cases # isn't available to context,
// we may be passing it in explicitly for helper urls
var secondPartSplit = urlSecondPart.Split('#');
var querystring = secondPartSplit[0];
var hashUrlPart = string.Empty;
if (secondPartSplit.Length > 1)
{
hashUrlPart = "#" + secondPartSplit[1];
}
var nvc = HttpUtility.ParseQueryString(querystring);
if (!nvc.HasKeys()) return url;
// Remove any matches
foreach (var key in nvc.AllKeys)
{
if (paramsToRemove.Contains(key))
{
nvc.Remove(key);
}
}
if (!nvc.HasKeys()) return urlFirstPart;
return urlFirstPart +
"?" + string.Join("&", nvc.AllKeys.Select(c => c.ToString() + "=" + nvc[c.ToString()])) +
hashUrlPart;
}
A more modern answer for this old question in case someone else stumbles across it like I did.
This is using the Uri class to parse the URL (can be skipped if your URL is already in a Uri object) and LINQ to filter the query string.
public static string RemoveQueryStringByKey(string url, string key)
{
var uri = new Uri(url, UriKind.Absolute);
var queryParts = uri.Query
.TrimStart('?')
.Split('&')
.Where(item => string.CompareOrdinal(item, key) != 0);
return uri.Scheme + Uri.SchemeDelimiter
+ uri.Authority
+ uri.AbsolutePath
+ "?" + string.Join("&", queryParts);
}
With reusing the signature from the accepted answer, but preserving the fragment and using QueryHelpers from Microsoft.AspNetCore.WebUtilities.
public static string RemoveQueryStringByKey(string url, string key)
{
var uri = new Uri(url);
var newQueryString = QueryHelpers.ParseQuery(uri.Query);
if (newQueryString.Remove(key))
{
var urlWithNewQuery = QueryHelpers.AddQueryString(
uri.GetLeftPart(UriPartial.Path),
newQueryString.ToDictionary(
queryParam => queryParam.Key,
queryParam => queryParam.Value.ToString()))
return $"{urlWithNewQuery}{uri.Fragment}";
}
return url;
}
string url = HttpContext.Current.Request.Url.AbsoluteUri;
string[] separateURL = url.Split('?');
NameValueCollection queryString = System.Web.HttpUtility.ParseQueryString(separateURL[1]);
queryString.Remove("param_toremove");
string revisedurl = separateURL[0] + "?" + queryString.ToString();