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RegexPathSpec documentation and MatchedPath improvements (#8163)
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* More documentation

Signed-off-by: Joakim Erdfelt <joakim.erdfelt@gmail.com>
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@joakime
joakime authored Jun 16, 2022
1 parent 1f902f6 commit 1b4f941
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262 changes: 178 additions & 84 deletions jetty-http/src/main/java/org/eclipse/jetty/http/pathmap/RegexPathSpec.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,77 @@
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
* <p>
* RegexPathSpec is a PathSpec implementation for a {@link PathMappings} instance.
* </p>
*
* <p>
* Supports the standard Java regex found in {@link java.util.regex.Pattern}.
* </p>
*
* <p>
* Supports {@link PathSpecGroup} for {@link PathSpecGroup#EXACT}, {@link PathSpecGroup#PREFIX_GLOB}, {@link PathSpecGroup#MIDDLE_GLOB}, and {@link PathSpecGroup#SUFFIX_GLOB}.
* This is done by evaluating the signature or the provided regex pattern for what is a literal vs a glob (of any kind).
* </p>
*
* <ul>
* <li>Only literals, it's a {@link PathSpecGroup#EXACT}.</li>
* <li>Starts with literals, ends with globs, it's a {@link PathSpecGroup#PREFIX_GLOB}</li>
* <li>Starts with glob, has at least 1 literal, then any thing else, it's a {@link PathSpecGroup#SUFFIX_GLOB}</li>
* <li>All other signatures are a {@link PathSpecGroup#MIDDLE_GLOB}</li>
* </ul>
*
* <p>
* The use of regex capture groups, regex character classes, regex quantifiers, and regex special contructs
* will be identified as a glob (for signature determination), all other characters are identified
* as literal. The regex {@code ^} beginning of line, and regex {@code $} end of line are ignored.
* </p>
*
* <p>
* <b>Support for {@link MatchedPath} and PathMatch vs PathInfo</b>
* </p>
*
* <p>
* There's a few steps in evaluating the matched input path for determining where the split
* in the input path should occur for {@link MatchedPath#getPathMatch()} and {@link MatchedPath#getPathInfo()}.
* </p>
*
* <ol>
* <li>
* If there are no regex capturing groups,
* the entire path is returned in {@link MatchedPath#getPathMatch()},
* and a null returned for {@link MatchedPath#getPathInfo()}
* </li>
* <li>
* If both the named regex capturing groups {@code name} and {@code info} are present, then
* the {@code name} group is returned in {@link MatchedPath#getPathMatch()} and the
* {@code info} group is returned in {@link MatchedPath#getPathInfo()}
* </li>
* <li>
* If there is only 1 regex capturing group
* <ul>
* <li>
* If the named regex capturing group {@code name} is present, the
* input path up to the end of the capturing group is returned
* in {@link MatchedPath#getPathMatch()} and any following characters (or null)
* are returned in {@link MatchedPath#getPathInfo()}
* </li>
* <li>
* other wise the input path up to the start of the capturing group is returned
* in {@link MatchedPath#getPathMatch()} and any following characters (or null)
* are returned in {@link MatchedPath#getPathInfo()}
* </li>
* </ul>
* If the split on pathMatch ends with {@code /} AND the pathInfo doesn't start with {@code /}
* then the slash is moved from pathMatch to pathInfo.
* </li>
* <li>
* All other RegexPathSpec signatures will return the entire path
* in {@link MatchedPath#getPathMatch()}, and a null returned for {@link MatchedPath#getPathInfo()}
* </li>
* </ol>
*/
public class RegexPathSpec extends AbstractPathSpec
{
private static final Logger LOG = LoggerFactory.getLogger(UriTemplatePathSpec.class);
Expand Down Expand Up @@ -54,8 +125,9 @@ public RegexPathSpec(String regex)
declaration = regex;
int specLength = declaration.length();
// build up a simple signature we can use to identify the grouping
boolean inTextList = false;
boolean inCharacterClass = false;
boolean inQuantifier = false;
boolean inCaptureGroup = false;
StringBuilder signature = new StringBuilder();

int pathDepth = 0;
Expand All @@ -68,8 +140,6 @@ public RegexPathSpec(String regex)
case '^': // ignore anchors
case '$': // ignore anchors
case '\'': // ignore escaping
case '(': // ignore grouping
case ')': // ignore grouping
break;
case '+': // single char quantifier
case '?': // single char quantifier
Expand All @@ -78,25 +148,32 @@ public RegexPathSpec(String regex)
case '.': // any char token
signature.append('g'); // glob
break;
case '{':
case '(': // in regex capture group
inCaptureGroup = true;
break;
case ')':
inCaptureGroup = false;
signature.append('g');
break;
case '{': // in regex quantifier
inQuantifier = true;
break;
case '}':
inQuantifier = false;
break;
case '[':
inTextList = true;
case '[': // in regex character class
inCharacterClass = true;
break;
case ']':
inTextList = false;
inCharacterClass = false;
signature.append('g'); // glob
break;
case '/':
if (!inTextList && !inQuantifier)
if (!inCharacterClass && !inQuantifier && !inCaptureGroup)
pathDepth++;
break;
default:
if (!inTextList && !inQuantifier && Character.isLetterOrDigit(c))
if (!inCharacterClass && !inQuantifier && !inCaptureGroup && Character.isLetterOrDigit(c))
{
if (last == '\\') // escaped
{
Expand Down Expand Up @@ -135,9 +212,9 @@ public RegexPathSpec(String regex)
String sig = signature.toString();

PathSpecGroup group;
if (Pattern.matches("^l*$", sig))
if (Pattern.matches("^l+$", sig))
group = PathSpecGroup.EXACT;
else if (Pattern.matches("^l*g+", sig))
else if (Pattern.matches("^l+g+", sig))
group = PathSpecGroup.PREFIX_GLOB;
else if (Pattern.matches("^g+l+.*", sig))
group = PathSpecGroup.SUFFIX_GLOB;
Expand Down Expand Up @@ -193,44 +270,19 @@ public int getPathDepth()
@Override
public String getPathInfo(String path)
{
// Path Info only valid for PREFIX_GLOB types
if (_group == PathSpecGroup.PREFIX_GLOB)
{
Matcher matcher = getMatcher(path);
if (matcher.matches())
{
if (matcher.groupCount() >= 1)
{
String pathInfo = matcher.group(1);
if ("".equals(pathInfo))
return "/";
else
return pathInfo;
}
}
}
return null;
MatchedPath matched = matched(path);
if (matched == null)
return null;
return matched.getPathInfo();
}

@Override
public String getPathMatch(String path)
{
Matcher matcher = getMatcher(path);
if (matcher.matches())
{
if (_group == PathSpecGroup.PREFIX_GLOB && matcher.groupCount() >= 1)
{
int idx = matcher.start(1);
if (idx > 0)
{
if (path.charAt(idx - 1) == '/')
idx--;
return path.substring(0, idx);
}
}
return path;
}
return null;
MatchedPath matched = matched(path);
if (matched == null)
return "";
return matched.getPathMatch();
}

@Override
Expand Down Expand Up @@ -277,74 +329,117 @@ private class RegexMatchedPath implements MatchedPath
{
private final RegexPathSpec pathSpec;
private final String path;
private final Matcher matcher;
private String pathMatch;
private String pathInfo;

public RegexMatchedPath(RegexPathSpec regexPathSpec, String path, Matcher matcher)
{
this.pathSpec = regexPathSpec;
this.path = path;
this.matcher = matcher;

calcPathMatchInfo(matcher);
}

@Override
public String getPathMatch()
private void calcPathMatchInfo(Matcher matcher)
{
try
{
String p = matcher.group("name");
if (p != null)
{
return p;
}
}
catch (IllegalArgumentException ignore)
int groupCount = matcher.groupCount();


if (groupCount == 0)
{
// ignore if group name not found.
pathMatch = path;
pathInfo = null;
return;
}

if (pathSpec.getGroup() == PathSpecGroup.PREFIX_GLOB && matcher.groupCount() >= 1)
if (groupCount == 1)
{
// we know we are splitting
int idxNameEnd = endOf(matcher, "name");
if (idxNameEnd >= 0)
{
pathMatch = path.substring(0, idxNameEnd);
pathInfo = path.substring(idxNameEnd);

// If split on pathMatch ends with '/'
// AND pathInfo doesn't have one, move the slash to pathInfo only move 1 level
if (pathMatch.length() > 0 && pathMatch.charAt(pathMatch.length() - 1) == '/' &&
!pathInfo.startsWith("/"))
{
pathMatch = pathMatch.substring(0, pathMatch.length() - 1);
pathInfo = '/' + pathInfo;
}
return;
}

// Use start of anonymous group
int idx = matcher.start(1);
if (idx > 0)
if (idx >= 0)
{
if (this.path.charAt(idx - 1) == '/')
idx--;
return this.path.substring(0, idx);
pathMatch = path.substring(0, idx);
pathInfo = path.substring(idx);

if (pathMatch.length() > 0 && pathMatch.charAt(pathMatch.length() - 1) == '/' &&
!pathInfo.startsWith("/"))
{
pathMatch = pathMatch.substring(0, pathMatch.length() - 1);
pathInfo = '/' + pathInfo;
}
return;
}
}

// default is the full path
return this.path;
// Reach here we have 2+ groups

String gName = valueOf(matcher, "name");
String gInfo = valueOf(matcher, "info");

// if both named groups exist
if (gName != null && gInfo != null)
{
pathMatch = gName;
pathInfo = gInfo;
return;
}

pathMatch = path;
pathInfo = null;
}

@Override
public String getPathInfo()
private String valueOf(Matcher matcher, String groupName)
{
try
{
String p = matcher.group("info");
if (p != null)
{
return p;
}
return matcher.group(groupName);
}
catch (IllegalArgumentException ignore)
catch (IllegalArgumentException notFound)
{
// ignore if group info not found.
return null;
}
}

// Path Info only valid for PREFIX_GLOB
if (pathSpec.getGroup() == PathSpecGroup.PREFIX_GLOB && matcher.groupCount() >= 1)
private int endOf(Matcher matcher, String groupName)
{
try
{
return matcher.end(groupName);
}
catch (IllegalArgumentException notFound)
{
String pathInfo = matcher.group(1);
if ("".equals(pathInfo))
return "/";
else
return pathInfo;
return -2;
}
}

// default is null
return null;
@Override
public String getPathMatch()
{
return this.pathMatch;
}

@Override
public String getPathInfo()
{
return this.pathInfo;
}

@Override
Expand All @@ -353,7 +448,6 @@ public String toString()
return getClass().getSimpleName() + "[" +
"pathSpec=" + pathSpec +
", path=\"" + path + "\"" +
", matcher=" + matcher +
']';
}
}
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