Standard URL encode function?

Question

Is there a Delphi equivalent of this .net's method:

Url.UrlEncode()

Note
I haven't worked with Delphi for several years now. As I read through the answers I notice that there are several remarks and alternatives to the currently marked answer. I haven't had the opportunity to test them so I'm basing my answer on the most upvoted.
For your own sake, do check later answers and after deciding upvote the best answer so everybody can benefit from your experience.

Answer 1

Look at indy IdURI unit, it has two static methods in the TIdURI class for Encode/Decode the URL.

uses
  IdURI;

..
begin
  S := TIdURI.URLEncode(str);
//
  S := TIdURI.URLDecode(str);
end;

Answer 2

Another simple way of doing this is to use the HTTPEncode function in the HTTPApp unit - very roughly

Uses 
  HTTPApp;

function URLEncode(const s : string) : string;
begin
  result := HTTPEncode(s);
end

---

HTTPEncode is deprecated in Delphi 10.3 - 'Use TNetEncoding.URL.Decode'

Uses
  NetEncoding;

function URLEncode(const s : string) : string;
begin
  result := TNetEncoding.URL.Encode(s);
end

Answer 3

Since Delphi xe7 you can use TNetEncoding.Url.Encode()

Answer 4

I made myself this function to encode everything except really safe characters. Especially I had problems with +. Be aware that you can not encode the whole URL with this function but you need to encdoe the parts that you want to have no special meaning, typically the values of the variables.

function MyEncodeUrl(source:string):string;
 var i:integer;
 begin
   result := '';
   for i := 1 to length(source) do
       if not (source[i] in ['A'..'Z','a'..'z','0','1'..'9','-','_','~','.']) then result := result + '%'+inttohex(ord(source[i]),2) else result := result + source[i];
 end;

Answer 5

Another option, is to use the Synapse library which has a simple URL encoding method (as well as many others) in the SynaCode unit.

uses
  SynaCode;
..
begin
  s := EncodeUrl( str );
//
  s := DecodeUrl( str );
end;

Answer 6

Update 2018: the code shown below seems to be outdated. see Remy's comment.

class function TIdURI.ParamsEncode(const ASrc: string): string;
var
  i: Integer;
const
  UnsafeChars = '*#%<> []';  {do not localize}
begin
  Result := '';    {Do not Localize}
  for i := 1 to Length(ASrc) do
  begin
    if CharIsInSet(ASrc, i, UnsafeChars) or (not CharIsInSet(ASrc, i, CharRange(#33,#128))) then begin {do not localize}
      Result := Result + '%' + IntToHex(Ord(ASrc[i]), 2);  {do not localize}
    end else begin
      Result := Result + ASrc[i];
    end;
  end;
end;

From Indy.

---

Anyway Indy is not working properly so YOU NEED TO SEE THIS ARTICLE:
http://marc.durdin.net/2012/07/indy-tiduri-pathencode-urlencode-and-paramsencode-and-more/

Answer 7

In recent versions of Delphi (tested with XE5), use the URIEncode function in the REST.Utils unit.

Answer 8

In a non-dotnet environment, the Wininet unit provides access to Windows' WinHTTP encode function: InternetCanonicalizeUrl

Answer 9

I was also facing the same issue (Delphi 4).

I resolved the issue using below mentioned function:

function fnstUrlEncodeUTF8(stInput : widestring) : string;
  const
    hex : array[0..255] of string = (
     '%00', '%01', '%02', '%03', '%04', '%05', '%06', '%07',
     '%08', '%09', '%0a', '%0b', '%0c', '%0d', '%0e', '%0f',
     '%10', '%11', '%12', '%13', '%14', '%15', '%16', '%17',
     '%18', '%19', '%1a', '%1b', '%1c', '%1d', '%1e', '%1f',
     '%20', '%21', '%22', '%23', '%24', '%25', '%26', '%27',
     '%28', '%29', '%2a', '%2b', '%2c', '%2d', '%2e', '%2f',
     '%30', '%31', '%32', '%33', '%34', '%35', '%36', '%37',
     '%38', '%39', '%3a', '%3b', '%3c', '%3d', '%3e', '%3f',
     '%40', '%41', '%42', '%43', '%44', '%45', '%46', '%47',
     '%48', '%49', '%4a', '%4b', '%4c', '%4d', '%4e', '%4f',
     '%50', '%51', '%52', '%53', '%54', '%55', '%56', '%57',
     '%58', '%59', '%5a', '%5b', '%5c', '%5d', '%5e', '%5f',
     '%60', '%61', '%62', '%63', '%64', '%65', '%66', '%67',
     '%68', '%69', '%6a', '%6b', '%6c', '%6d', '%6e', '%6f',
     '%70', '%71', '%72', '%73', '%74', '%75', '%76', '%77',
     '%78', '%79', '%7a', '%7b', '%7c', '%7d', '%7e', '%7f',
     '%80', '%81', '%82', '%83', '%84', '%85', '%86', '%87',
     '%88', '%89', '%8a', '%8b', '%8c', '%8d', '%8e', '%8f',
     '%90', '%91', '%92', '%93', '%94', '%95', '%96', '%97',
     '%98', '%99', '%9a', '%9b', '%9c', '%9d', '%9e', '%9f',
     '%a0', '%a1', '%a2', '%a3', '%a4', '%a5', '%a6', '%a7',
     '%a8', '%a9', '%aa', '%ab', '%ac', '%ad', '%ae', '%af',
     '%b0', '%b1', '%b2', '%b3', '%b4', '%b5', '%b6', '%b7',
     '%b8', '%b9', '%ba', '%bb', '%bc', '%bd', '%be', '%bf',
     '%c0', '%c1', '%c2', '%c3', '%c4', '%c5', '%c6', '%c7',
     '%c8', '%c9', '%ca', '%cb', '%cc', '%cd', '%ce', '%cf',
     '%d0', '%d1', '%d2', '%d3', '%d4', '%d5', '%d6', '%d7',
     '%d8', '%d9', '%da', '%db', '%dc', '%dd', '%de', '%df',
     '%e0', '%e1', '%e2', '%e3', '%e4', '%e5', '%e6', '%e7',
     '%e8', '%e9', '%ea', '%eb', '%ec', '%ed', '%ee', '%ef',
     '%f0', '%f1', '%f2', '%f3', '%f4', '%f5', '%f6', '%f7',
     '%f8', '%f9', '%fa', '%fb', '%fc', '%fd', '%fe', '%ff');
 var
   iLen,iIndex : integer;
   stEncoded : string;
   ch : widechar;
 begin
   iLen := Length(stInput);
   stEncoded := '';
   for iIndex := 1 to iLen do
   begin
     ch := stInput[iIndex];
     if (ch >= 'A') and (ch <= 'Z') then
       stEncoded := stEncoded + ch
     else if (ch >= 'a') and (ch <= 'z') then
       stEncoded := stEncoded + ch
     else if (ch >= '0') and (ch <= '9') then
       stEncoded := stEncoded + ch
     else if (ch = ' ') then
       stEncoded := stEncoded + '+'
     else if ((ch = '-') or (ch = '_') or (ch = '.') or (ch = '!') or (ch = '*')
       or (ch = '~') or (ch = '\')  or (ch = '(') or (ch = ')')) then
       stEncoded := stEncoded + ch
     else if (Ord(ch) <= $07F) then
       stEncoded := stEncoded + hex[Ord(ch)]
     else if (Ord(ch) <= $7FF) then
     begin
        stEncoded := stEncoded + hex[$c0 or (Ord(ch) shr 6)];
        stEncoded := stEncoded + hex[$80 or (Ord(ch) and $3F)];
     end
     else
     begin
        stEncoded := stEncoded + hex[$e0 or (Ord(ch) shr 12)];
        stEncoded := stEncoded + hex[$80 or ((Ord(ch) shr 6) and ($3F))];
        stEncoded := stEncoded + hex[$80 or ((Ord(ch)) and ($3F))];
     end;
   end;
   result := (stEncoded);
 end;

source : Java source code

Answer 10

I have made my own function. It converts spaces to %20, not to plus sign. It was needed to convert local file path to path for browser (with file:/// prefix). The most important is it handles UTF-8 strings. It was inspired by Radek Hladik's solution above.

function URLEncode(s: string): string;
var
  i: integer;
  source: PAnsiChar;
begin
  result := '';
  source := pansichar(s);
  for i := 1 to length(source) do
    if not (source[i - 1] in ['A'..'Z', 'a'..'z', '0'..'9', '-', '_', '~', '.', ':', '/']) then
      result := result + '%' + inttohex(ord(source[i - 1]), 2)
    else
      result := result + source[i - 1];
end;       

Answer 11

AFAIK you need to make your own.

Here is an example.

• HTTPEncode

Answer 12

TIdUri or HTTPEncode has problems with unicode charactersets. Function below will do correct encoding for you.

function EncodeURIComponent(const ASrc: string): UTF8String;
const
  HexMap: UTF8String = '0123456789ABCDEF';

  function IsSafeChar(ch: Integer): Boolean;
  begin
    if (ch >= 48) and (ch <= 57) then Result := True    // 0-9
    else if (ch >= 65) and (ch <= 90) then Result := True  // A-Z
    else if (ch >= 97) and (ch <= 122) then Result := True  // a-z
    else if (ch = 33) then Result := True // !
    else if (ch >= 39) and (ch <= 42) then Result := True // '()*
    else if (ch >= 45) and (ch <= 46) then Result := True // -.
    else if (ch = 95) then Result := True // _
    else if (ch = 126) then Result := True // ~
    else Result := False;
  end;
var
  I, J: Integer;
  ASrcUTF8: UTF8String;
begin
  Result := '';    {Do not Localize}

  ASrcUTF8 := UTF8Encode(ASrc);
  // UTF8Encode call not strictly necessary but
  // prevents implicit conversion warning

  I := 1; J := 1;
  SetLength(Result, Length(ASrcUTF8) * 3); // space to %xx encode every byte
  while I <= Length(ASrcUTF8) do
  begin
    if IsSafeChar(Ord(ASrcUTF8[I])) then
    begin
      Result[J] := ASrcUTF8[I];
      Inc(J);
    end
    else if ASrcUTF8[I] = ' ' then
    begin
      Result[J] := '+';
      Inc(J);
    end
    else
    begin
      Result[J] := '%';
      Result[J+1] := HexMap[(Ord(ASrcUTF8[I]) shr 4) + 1];
      Result[J+2] := HexMap[(Ord(ASrcUTF8[I]) and 15) + 1];
      Inc(J,3);
    end;
    Inc(I);
  end;

  SetLength(Result, J-1);
end;

Answer 13

I'd like to point out that if you care much more about correctness than about efficiency, the simplest you can do is hex encode every character, even if it's not strictly necessary.

Just today I needed to encode a few parameters for a basic HTML login form submission. After going through all the options, each with their own caveats, I decided to write this naive version that works perfectly:

function URLEncode(const AStr: string): string;
var
  LBytes: TBytes;
  LIndex: Integer;
begin
  Result := '';
  LBytes := TEncoding.UTF8.GetBytes(AStr);
  for LIndex := Low(LBytes) to High(LBytes) do
    Result := Result + '%' + IntToHex(LBytes[LIndex], 2);
end;