net.dv8tion.jda.api.utils.MarkdownSanitizer Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of JDA Show documentation
Show all versions of JDA Show documentation
Java wrapper for the popular chat & VOIP service: Discord https://discord.com
/*
* Copyright 2015 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.dv8tion.jda.api.utils;
import gnu.trove.map.TIntObjectMap;
import gnu.trove.map.hash.TIntObjectHashMap;
import net.dv8tion.jda.internal.utils.Checks;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.regex.Pattern;
/**
* Implements an algorithm that can strip or replace markdown in any supplied string.
*
* @see #sanitize(String, net.dv8tion.jda.api.utils.MarkdownSanitizer.SanitizationStrategy)
*
* @since 4.0.0
*/
public class MarkdownSanitizer
{
/** Normal characters that are not special for markdown, ignoring this has no effect */
public static final int NORMAL = 0;
/** Bold region such as "**Hello**" */
public static final int BOLD = 1 << 0;
/** Italics region for underline such as "_Hello_" */
public static final int ITALICS_U = 1 << 1;
/** Italics region for asterisks such as "*Hello*" */
public static final int ITALICS_A = 1 << 2;
/** Monospace region such as "`Hello`" */
public static final int MONO = 1 << 3;
/** Monospace region such as "``Hello``" */
public static final int MONO_TWO = 1 << 4;
/** Codeblock region such as "```Hello```" */
public static final int BLOCK = 1 << 5;
/** Spoiler region such as "||Hello||" */
public static final int SPOILER = 1 << 6;
/** Underline region such as "__Hello__" */
public static final int UNDERLINE = 1 << 7;
/** Strikethrough region such as "~~Hello~~" */
public static final int STRIKE = 1 << 8;
/** Quote region such as {@code "> text here"} */
public static final int QUOTE = 1 << 9;
/** Quote block region such as {@code ">>> text here"} */
public static final int QUOTE_BLOCK = 1 << 10;
private static final int ESCAPED_BOLD = Integer.MIN_VALUE | BOLD;
private static final int ESCAPED_ITALICS_U = Integer.MIN_VALUE | ITALICS_U;
private static final int ESCAPED_ITALICS_A = Integer.MIN_VALUE | ITALICS_A;
private static final int ESCAPED_MONO = Integer.MIN_VALUE | MONO;
private static final int ESCAPED_MONO_TWO = Integer.MIN_VALUE | MONO_TWO;
private static final int ESCAPED_BLOCK = Integer.MIN_VALUE | BLOCK;
private static final int ESCAPED_SPOILER = Integer.MIN_VALUE | SPOILER;
private static final int ESCAPED_UNDERLINE = Integer.MIN_VALUE | UNDERLINE;
private static final int ESCAPED_STRIKE = Integer.MIN_VALUE | STRIKE;
private static final int ESCAPED_QUOTE = Integer.MIN_VALUE | QUOTE;
private static final int ESCAPED_QUOTE_BLOCK = Integer.MIN_VALUE | QUOTE_BLOCK;
private static final Pattern codeLanguage = Pattern.compile("^\\w+\n.*", Pattern.MULTILINE | Pattern.DOTALL);
private static final Pattern quote = Pattern.compile("> +.*", Pattern.DOTALL | Pattern.MULTILINE);
private static final Pattern quoteBlock = Pattern.compile(">>>\\s+\\S.*", Pattern.DOTALL | Pattern.MULTILINE);
private static final TIntObjectMap tokens;
static
{
tokens = new TIntObjectHashMap<>();
tokens.put(NORMAL, "");
tokens.put(BOLD, "**");
tokens.put(ITALICS_U, "_");
tokens.put(ITALICS_A, "*");
tokens.put(BOLD | ITALICS_A, "***");
tokens.put(MONO, "`");
tokens.put(MONO_TWO, "``");
tokens.put(BLOCK, "```");
tokens.put(SPOILER, "||");
tokens.put(UNDERLINE, "__");
tokens.put(STRIKE, "~~");
}
private int ignored;
private SanitizationStrategy strategy;
public MarkdownSanitizer()
{
this.ignored = NORMAL;
this.strategy = SanitizationStrategy.REMOVE;
}
public MarkdownSanitizer(int ignored, @Nullable SanitizationStrategy strategy)
{
this.ignored = ignored;
this.strategy = strategy == null ? SanitizationStrategy.REMOVE : strategy;
}
/**
* Sanitize string with default settings.
*
Same as {@code sanitize(sequence, SanitizationStrategy.REMOVE)}
*
* @param sequence
* The string to sanitize
*
* @return The sanitized string
*/
@Nonnull
public static String sanitize(@Nonnull String sequence)
{
return sanitize(sequence, SanitizationStrategy.REMOVE);
}
/**
* Sanitize string without ignoring anything.
*
* @param sequence
* The string to sanitize
* @param strategy
* The {@link net.dv8tion.jda.api.utils.MarkdownSanitizer.SanitizationStrategy} to apply
*
* @throws java.lang.IllegalArgumentException
* If provided with null
*
* @return The sanitized string
*
* @see MarkdownSanitizer#MarkdownSanitizer()
* @see #withIgnored(int)
*/
@Nonnull
public static String sanitize(@Nonnull String sequence, @Nonnull SanitizationStrategy strategy)
{
Checks.notNull(sequence, "String");
Checks.notNull(strategy, "Strategy");
return new MarkdownSanitizer().withStrategy(strategy).compute(sequence);
}
/**
* Escapes every markdown formatting found in the provided string.
*
* @param sequence
* The string to sanitize
*
* @throws java.lang.IllegalArgumentException
* If provided with null
*
* @return The string with escaped markdown
*
* @see #escape(String, int)
*/
@Nonnull
public static String escape(@Nonnull String sequence)
{
return escape(sequence, NORMAL);
}
/**
* Escapes every markdown formatting found in the provided string.
*
Example: {@code escape("**Hello** ~~World~~!", MarkdownSanitizer.BOLD | MarkdownSanitizer.STRIKE)}
*
* @param sequence
* The string to sanitize
* @param ignored
* Formats to ignore
*
* @throws java.lang.IllegalArgumentException
* If provided with null
*
* @return The string with escaped markdown
*/
@Nonnull
public static String escape(@Nonnull String sequence, int ignored)
{
return new MarkdownSanitizer()
.withIgnored(ignored)
.withStrategy(SanitizationStrategy.ESCAPE)
.compute(sequence);
}
/**
* Escapes every single markdown formatting token found in the provided string.
*
Example: {@code escape("**Hello _World_", true)}
*
* @param sequence
* The string to sanitize
* @param single
* Whether it should scape single tokens or not.
*
* @throws java.lang.IllegalArgumentException
* If provided with null sequence
*
* @return The string with escaped markdown
*/
@Nonnull
public static String escape(@Nonnull String sequence, boolean single)
{
Checks.notNull(sequence, "Input");
if(!single) return escape(sequence);
StringBuilder builder = new StringBuilder();
boolean escaped = false;
boolean newline = true;
for (int i = 0; i < sequence.length(); i++)
{
char current = sequence.charAt(i);
if (newline)
{
newline = Character.isWhitespace(current); // might still be a quote if prefixed by whitespace
if (current == '>')
{
// Check for quote if line starts with angle bracket
if (i + 1 < sequence.length() && Character.isWhitespace(sequence.charAt(i+1)))
{
builder.append("\\>"); // simple quote
}
else if (i + 3 < sequence.length() && sequence.startsWith(">>>", i) && Character.isWhitespace(sequence.charAt(i+3)))
{
builder.append("\\>\\>\\>").append(sequence.charAt(i+3)); // block quote
i += 3; // since we include 3 angle brackets AND whitespace
}
else
{
builder.append(current); // just a normal angle bracket
}
continue;
}
}
if (escaped)
{
builder.append(current);
escaped = false;
continue;
}
// Handle average case
switch (current)
{
case '*': // simple markdown escapes for single characters
case '_':
case '`':
builder.append('\\').append(current);
break;
case '|': // cases that require at least 2 characters in sequence
case '~':
if (i + 1 < sequence.length() && sequence.charAt(i+1) == current)
{
builder.append('\\').append(current)
.append('\\').append(current);
i++;
}
else
builder.append(current);
break;
case '\\': // escape character
builder.append(current);
escaped = true;
break;
case '\n': // linefeed is a special case for quotes
builder.append(current);
newline = true;
break;
default:
builder.append(current);
}
}
return builder.toString();
}
/**
* Switches the used {@link net.dv8tion.jda.api.utils.MarkdownSanitizer.SanitizationStrategy}.
*
* @param strategy
* The new strategy
*
* @throws java.lang.IllegalArgumentException
* If provided with null
*
* @return The current sanitizer instance with the new strategy
*/
@Nonnull
public MarkdownSanitizer withStrategy(@Nonnull SanitizationStrategy strategy)
{
Checks.notNull(strategy, "Strategy");
this.strategy = strategy;
return this;
}
/**
* Specific regions to ignore.
*
Example: {@code new MarkdownSanitizer().withIgnored(MarkdownSanitizer.BOLD | MarkdownSanitizer.UNDERLINE).compute("Hello __world__!")}
*
* @param ignored
* The regions to ignore
*
* @return The current sanitizer instance with the new ignored regions
*/
@Nonnull
public MarkdownSanitizer withIgnored(int ignored)
{
this.ignored |= ignored;
return this;
}
private int getRegion(int index, @Nonnull String sequence)
{
if (sequence.length() - index >= 3)
{
String threeChars = sequence.substring(index, index + 3);
switch (threeChars)
{
case "```":
return doesEscape(index, sequence) ? ESCAPED_BLOCK : BLOCK;
case "***":
return doesEscape(index, sequence) ? ESCAPED_BOLD | ITALICS_A : BOLD | ITALICS_A;
}
}
if (sequence.length() - index >= 2)
{
String twoChars = sequence.substring(index, index + 2);
switch (twoChars)
{
case "**":
return doesEscape(index, sequence) ? ESCAPED_BOLD : BOLD;
case "__":
return doesEscape(index, sequence) ? ESCAPED_UNDERLINE : UNDERLINE;
case "~~":
return doesEscape(index, sequence) ? ESCAPED_STRIKE : STRIKE;
case "``":
return doesEscape(index, sequence) ? ESCAPED_MONO_TWO : MONO_TWO;
case "||":
return doesEscape(index, sequence) ? ESCAPED_SPOILER : SPOILER;
}
}
char current = sequence.charAt(index);
switch (current)
{
case '*':
return doesEscape(index, sequence) ? ESCAPED_ITALICS_A : ITALICS_A;
case '_':
return doesEscape(index, sequence) ? ESCAPED_ITALICS_U : ITALICS_U;
case '`':
return doesEscape(index, sequence) ? ESCAPED_MONO : MONO;
}
return NORMAL;
}
private boolean hasCollision(int index, @Nonnull String sequence, char c)
{
if (index < 0)
return false;
return index < sequence.length() - 1 && sequence.charAt(index + 1) == c;
}
private int findEndIndex(int afterIndex, int region, @Nonnull String sequence)
{
if (isEscape(region))
return -1;
int lastMatch = afterIndex + getDelta(region) + 1;
while (lastMatch != -1)
{
switch (region)
{
case BOLD | ITALICS_A:
lastMatch = sequence.indexOf("***", lastMatch);
break;
case BOLD:
lastMatch = sequence.indexOf("**", lastMatch);
if (lastMatch != -1 && hasCollision(lastMatch + 1, sequence, '*')) // did we find a bold italics tag?
{
lastMatch += 3;
continue;
}
break;
case ITALICS_A:
lastMatch = sequence.indexOf('*', lastMatch);
if (lastMatch != -1 && hasCollision(lastMatch, sequence, '*')) // did we find a bold tag?
{
if (hasCollision(lastMatch + 1, sequence, '*'))
lastMatch += 3;
else
lastMatch += 2;
continue;
}
break;
case UNDERLINE:
lastMatch = sequence.indexOf("__", lastMatch);
break;
case ITALICS_U:
lastMatch = sequence.indexOf('_', lastMatch);
if (lastMatch != -1 && hasCollision(lastMatch, sequence, '_')) // did we find an underline tag?
{
lastMatch += 2;
continue;
}
break;
case SPOILER:
lastMatch = sequence.indexOf("||", lastMatch);
break;
case BLOCK:
lastMatch = sequence.indexOf("```", lastMatch);
break;
case MONO_TWO:
lastMatch = sequence.indexOf("``", lastMatch);
if (lastMatch != -1 && hasCollision(lastMatch + 1, sequence, '`')) // did we find a codeblock?
{
lastMatch += 3;
continue;
}
break;
case MONO:
lastMatch = sequence.indexOf('`', lastMatch);
if (lastMatch != -1 && hasCollision(lastMatch, sequence, '`')) // did we find a codeblock?
{
if (hasCollision(lastMatch + 1, sequence, '`'))
lastMatch += 3;
else
lastMatch += 2;
continue;
}
break;
case STRIKE:
lastMatch = sequence.indexOf("~~", lastMatch);
break;
default:
return -1;
}
if (lastMatch == -1 || !doesEscape(lastMatch, sequence))
return lastMatch;
lastMatch++;
}
return -1;
}
@Nonnull
private String handleRegion(int start, int end, @Nonnull String sequence, int region)
{
String resolved = sequence.substring(start, end);
switch (region)
{
case BLOCK:
case MONO:
case MONO_TWO:
return resolved;
default:
return new MarkdownSanitizer(ignored, strategy).compute(resolved);
}
}
private int getDelta(int region)
{
switch (region)
{
case ESCAPED_BLOCK:
case ESCAPED_BOLD | ITALICS_A:
case BLOCK:
case BOLD | ITALICS_A:
return 3;
case ESCAPED_MONO_TWO:
case ESCAPED_BOLD:
case ESCAPED_UNDERLINE:
case ESCAPED_SPOILER:
case ESCAPED_STRIKE:
case MONO_TWO:
case BOLD:
case UNDERLINE:
case SPOILER:
case STRIKE:
return 2;
case ESCAPED_ITALICS_A:
case ESCAPED_ITALICS_U:
case ESCAPED_MONO:
case ESCAPED_QUOTE:
case ITALICS_A:
case ITALICS_U:
case MONO:
return 1;
default:
return 0;
}
}
private void applyStrategy(int region, @Nonnull String seq, @Nonnull StringBuilder builder)
{
if (strategy == SanitizationStrategy.REMOVE)
{
if (codeLanguage.matcher(seq).matches())
builder.append(seq.substring(seq.indexOf("\n") + 1));
else
builder.append(seq);
return;
}
String token = tokens.get(region);
if (token == null)
throw new IllegalStateException("Found illegal region for strategy ESCAPE '" + region + "' with no known format token!");
if (region == UNDERLINE)
token = "_\\_"; // UNDERLINE needs special handling because the client thinks its ITALICS_U if you only escape once
else if (region == BOLD)
token = "*\\*"; // BOLD needs special handling because the client thinks its ITALICS_A if you only escape once
else if (region == (BOLD | ITALICS_A))
token = "*\\*\\*"; // BOLD | ITALICS_A needs special handling because the client thinks its BOLD if you only escape once
builder.append("\\").append(token)
.append(seq)
.append("\\").append(token);
}
private boolean doesEscape(int index, @Nonnull String seq)
{
int backslashes = 0;
for (int i = index - 1; i > -1; i--)
{
if (seq.charAt(i) != '\\')
break;
backslashes++;
}
return backslashes % 2 != 0;
}
private boolean isEscape(int region)
{
return (Integer.MIN_VALUE & region) != 0;
}
private boolean isIgnored(int nextRegion)
{
return (nextRegion & ignored) == nextRegion;
}
/**
* Computes the provided input.
*
Uses the specified {@link net.dv8tion.jda.api.utils.MarkdownSanitizer.SanitizationStrategy} and
* ignores any regions specified with {@link #withIgnored(int)}.
*
* @param sequence
* The string to compute
*
* @throws java.lang.IllegalArgumentException
* If the provided string is null
*
* @return The resulting string after applying the computation
*/
@Nonnull
public String compute(@Nonnull String sequence)
{
Checks.notNull(sequence, "Input");
StringBuilder builder = new StringBuilder();
String end = handleQuote(sequence);
if (end != null) return end;
boolean onlySpacesSinceNewLine = true;
for (int i = 0; i < sequence.length();)
{
int nextRegion = getRegion(i, sequence);
char c = sequence.charAt(i);
boolean isNewLine = c == '\n';
boolean isSpace = c == ' ';
onlySpacesSinceNewLine = isNewLine || (onlySpacesSinceNewLine && isSpace);
if (nextRegion == NORMAL)
{
builder.append(sequence.charAt(i++));
if ((isNewLine || (isSpace && onlySpacesSinceNewLine)) && i < sequence.length())
{
String result = handleQuote(sequence.substring(i));
if (result != null)
return builder.append(result).toString();
}
continue;
}
int endRegion = findEndIndex(i, nextRegion, sequence);
if (isIgnored(nextRegion) || endRegion == -1)
{
int delta = getDelta(nextRegion);
for (int j = 0; j < delta; j++)
builder.append(sequence.charAt(i++));
continue;
}
int delta = getDelta(nextRegion);
applyStrategy(nextRegion, handleRegion(i + delta, endRegion, sequence, nextRegion), builder);
i = endRegion + delta;
}
return builder.toString();
}
private String handleQuote(@Nonnull String sequence)
{
// Special handling for quote
if (!isIgnored(QUOTE) && quote.matcher(sequence).matches())
{
int start = sequence.indexOf('>');
if (start < 0)
start = 0;
StringBuilder builder = new StringBuilder(compute(sequence.substring(start + 2)));
if (strategy == SanitizationStrategy.ESCAPE)
builder.insert(0, "\\> ");
return builder.toString();
}
else if (!isIgnored(QUOTE_BLOCK) && quoteBlock.matcher(sequence).matches())
{
if (strategy == SanitizationStrategy.ESCAPE)
return compute("\\".concat(sequence));
return compute(sequence.substring(4));
}
return null;
}
public enum SanitizationStrategy
{
/**
* Remove any format tokens that are not escaped or within a special region.
*
{@code "**Hello** World!" -> "Hello World!"}
*/
REMOVE,
/**
* Escape any format tokens that are not escaped or within a special region.
*
{@code "**Hello** World!" -> "\**Hello\** World!"}
*/
ESCAPE,
}
}