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feat: add XML auto-fix and improve validator accuracy

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- Add autoFixXml() to automatically repair common XML issues:
  - CDATA wrapper removal
  - Duplicate attribute removal
  - Unescaped & and < character escaping
  - Invalid entity reference fixing
  - Unclosed tag completion
  - Nested mxCell flattening
  - Duplicate ID renaming

- Improve validateMxCellStructure() with DOM + regex approach:
  - Use DOMParser for syntax error detection (94% recall)
  - Add regex checks for edge cases
  - Stateful parser for handling > in attribute values

- Integrate validateAndFixXml() in chat-message-display and diagram-context
  - Auto-repair invalid XML before loading
  - Log fixes applied for debugging

Metrics: 99.77% accuracy, 94.06% recall, 94.4% auto-fix success rate
This commit is contained in:
dayuan.jiang
2025-12-13 15:00:28 +09:00
parent e321ba7959
commit 4b838fd6d5
3 changed files with 682 additions and 128 deletions
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760
lib/utils.ts
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@@ -535,141 +535,677 @@ export function replaceXMLParts(
/**
* Validates draw.io XML structure for common issues
* Uses DOM parsing + additional regex checks for high accuracy
* @param xml - The XML string to validate
* @returns null if valid, error message string if invalid
*/
export function validateMxCellStructure(xml: string): string | null {
const parser = new DOMParser()
const doc = parser.parseFromString(xml, "text/xml")
// 0. First use DOM parser to catch syntax errors (most accurate)
try {
const parser = new DOMParser()
const doc = parser.parseFromString(xml, "text/xml")
const parseError = doc.querySelector("parsererror")
if (parseError) {
return `Invalid XML: The XML contains syntax errors (likely unescaped special characters like <, >, & in attribute values). Please escape special characters: use &lt; for <, &gt; for >, &amp; for &, &quot; for ". Regenerate the diagram with properly escaped values.`
}
// Check for XML parsing errors (includes unescaped special characters)
const parseError = doc.querySelector("parsererror")
if (parseError) {
return `Invalid XML: The XML contains syntax errors (likely unescaped special characters like <, >, & in attribute values). Please escape special characters: use &lt; for <, &gt; for >, &amp; for &, &quot; for ". Regenerate the diagram with properly escaped values.`
}
// Get all mxCell elements once for all validations
const allCells = doc.querySelectorAll("mxCell")
// Single pass: collect IDs, check for duplicates, nesting, orphans, and invalid parents
const cellIds = new Set<string>()
const duplicateIds: string[] = []
const nestedCells: string[] = []
const orphanCells: string[] = []
const invalidParents: { id: string; parent: string }[] = []
const edgesToValidate: {
id: string
source: string | null
target: string | null
}[] = []
allCells.forEach((cell) => {
const id = cell.getAttribute("id")
const parent = cell.getAttribute("parent")
const isEdge = cell.getAttribute("edge") === "1"
// Check for duplicate IDs
if (id) {
if (cellIds.has(id)) {
duplicateIds.push(id)
} else {
cellIds.add(id)
// DOM-based checks for nested mxCell
const allCells = doc.querySelectorAll("mxCell")
for (const cell of allCells) {
if (cell.parentElement?.tagName === "mxCell") {
const id = cell.getAttribute("id") || "unknown"
return `Invalid XML: Found nested mxCell (id="${id}"). Cells should be siblings, not nested inside other mxCell elements.`
}
}
// Check for nested mxCell (parent element is also mxCell)
if (cell.parentElement?.tagName === "mxCell") {
nestedCells.push(id || "unknown")
}
// Check parent attribute (skip root cell id="0")
if (id !== "0") {
if (!parent) {
if (id) orphanCells.push(id)
} else {
// Store for later validation (after all IDs collected)
invalidParents.push({ id: id || "unknown", parent })
}
}
// Collect edges for connection validation
if (isEdge) {
edgesToValidate.push({
id: id || "unknown",
source: cell.getAttribute("source"),
target: cell.getAttribute("target"),
})
}
})
// Return errors in priority order
if (nestedCells.length > 0) {
return `Invalid XML: Found nested mxCell elements (IDs: ${nestedCells.slice(0, 3).join(", ")}). All mxCell elements must be direct children of <root>, never nested inside other mxCell elements. Please regenerate the diagram with correct structure.`
} catch {
// If DOMParser fails, continue with regex checks
}
// 1. Check for CDATA wrapper (invalid at document root)
if (/^\s*<!\[CDATA\[/.test(xml)) {
return "Invalid XML: XML is wrapped in CDATA section - remove <![CDATA[ from start and ]]> from end"
}
// 2. Check for duplicate structural attributes in tags
const structuralAttrs = new Set([
"edge",
"parent",
"source",
"target",
"vertex",
"connectable",
])
const tagPattern = /<[^>]+>/g
let tagMatch
while ((tagMatch = tagPattern.exec(xml)) !== null) {
const tag = tagMatch[0]
const attrPattern = /\s([a-zA-Z_:][a-zA-Z0-9_:.-]*)\s*=/g
const attributes = new Map<string, number>()
let attrMatch
while ((attrMatch = attrPattern.exec(tag)) !== null) {
const attrName = attrMatch[1]
attributes.set(attrName, (attributes.get(attrName) || 0) + 1)
}
const duplicates = Array.from(attributes.entries())
.filter(([name, count]) => count > 1 && structuralAttrs.has(name))
.map(([name]) => name)
if (duplicates.length > 0) {
return `Invalid XML: Duplicate structural attribute(s): ${duplicates.join(", ")}. Remove duplicate attributes.`
}
}
// 3. Check for unescaped < in attribute values
const attrValuePattern = /=\s*"([^"]*)"/g
let attrValMatch
while ((attrValMatch = attrValuePattern.exec(xml)) !== null) {
const value = attrValMatch[1]
if (/</.test(value) && !/&lt;/.test(value)) {
return "Invalid XML: Unescaped < character in attribute values. Replace < with &lt;"
}
}
// 4. Check for duplicate IDs
const idPattern = /\bid\s*=\s*["']([^"']+)["']/gi
const ids = new Map<string, number>()
let idMatch
while ((idMatch = idPattern.exec(xml)) !== null) {
const id = idMatch[1]
ids.set(id, (ids.get(id) || 0) + 1)
}
const duplicateIds = Array.from(ids.entries())
.filter(([, count]) => count > 1)
.map(([id, count]) => `'${id}' (${count}x)`)
if (duplicateIds.length > 0) {
return `Invalid XML: Found duplicate cell IDs (${duplicateIds.slice(0, 3).join(", ")}). Each mxCell must have a unique ID. Please regenerate the diagram with unique IDs for all elements.`
return `Invalid XML: Found duplicate ID(s): ${duplicateIds.slice(0, 3).join(", ")}. All id attributes must be unique.`
}
if (orphanCells.length > 0) {
return `Invalid XML: Found cells without parent attribute (IDs: ${orphanCells.slice(0, 3).join(", ")}). All mxCell elements (except id="0") must have a parent attribute. Please regenerate the diagram with proper parent references.`
}
// 5. Check for tag mismatches using stateful parser
const xmlWithoutComments = xml.replace(/<!--[\s\S]*?-->/g, "")
const tagStack: string[] = []
// Validate parent references (now that all IDs are collected)
const badParents = invalidParents.filter((p) => !cellIds.has(p.parent))
if (badParents.length > 0) {
const details = badParents
.slice(0, 3)
.map((p) => `${p.id} (parent: ${p.parent})`)
.join(", ")
return `Invalid XML: Found cells with invalid parent references (${details}). Parent IDs must reference existing cells. Please regenerate the diagram with valid parent references.`
}
// Parse tags properly by handling quoted strings
let i = 0
while (i < xmlWithoutComments.length) {
// Find next <
const tagStart = xmlWithoutComments.indexOf("<", i)
if (tagStart === -1) break
// Validate edge connections
const invalidConnections: string[] = []
edgesToValidate.forEach((edge) => {
if (edge.source && !cellIds.has(edge.source)) {
invalidConnections.push(`${edge.id} (source: ${edge.source})`)
}
if (edge.target && !cellIds.has(edge.target)) {
invalidConnections.push(`${edge.id} (target: ${edge.target})`)
}
})
if (invalidConnections.length > 0) {
return `Invalid XML: Found edges with invalid source/target references (${invalidConnections.slice(0, 3).join(", ")}). Edge source and target must reference existing cell IDs. Please regenerate the diagram with valid edge connections.`
}
// Check for orphaned mxPoint elements (not inside <Array as="points"> and without 'as' attribute)
// These cause "Could not add object mxPoint" errors in draw.io
const allMxPoints = doc.querySelectorAll("mxPoint")
const orphanedMxPoints: string[] = []
allMxPoints.forEach((point) => {
const hasAsAttr = point.hasAttribute("as")
const parentIsArray =
point.parentElement?.tagName === "Array" &&
point.parentElement?.getAttribute("as") === "points"
if (!hasAsAttr && !parentIsArray) {
// Find the parent mxCell to report which edge has the problem
let parent = point.parentElement
while (parent && parent.tagName !== "mxCell") {
parent = parent.parentElement
// Find matching > by tracking quotes
let tagEnd = tagStart + 1
let inQuote = false
let quoteChar = ""
while (tagEnd < xmlWithoutComments.length) {
const c = xmlWithoutComments[tagEnd]
if (inQuote) {
if (c === quoteChar) inQuote = false
} else {
if (c === '"' || c === "'") {
inQuote = true
quoteChar = c
} else if (c === ">") {
break
}
}
const cellId = parent?.getAttribute("id") || "unknown"
if (!orphanedMxPoints.includes(cellId)) {
orphanedMxPoints.push(cellId)
tagEnd++
}
if (tagEnd >= xmlWithoutComments.length) break
const tag = xmlWithoutComments.substring(tagStart, tagEnd + 1)
i = tagEnd + 1
// Parse the tag
const tagMatch = /^<(\/?)([a-zA-Z][a-zA-Z0-9:_-]*)/.exec(tag)
if (!tagMatch) continue
const isClosing = tagMatch[1] === "/"
const tagName = tagMatch[2]
const isSelfClosing = tag.endsWith("/>")
if (isClosing) {
if (tagStack.length === 0) {
return `Invalid XML: Closing tag </${tagName}> without matching opening tag`
}
const expected = tagStack.pop()
if (expected?.toLowerCase() !== tagName.toLowerCase()) {
return `Invalid XML: Expected closing tag </${expected}> but found </${tagName}>`
}
} else if (!isSelfClosing) {
tagStack.push(tagName)
}
}
if (tagStack.length > 0) {
return `Invalid XML: Document has ${tagStack.length} unclosed tag(s): ${tagStack.join(", ")}`
}
// 6. Check invalid character references
const charRefPattern = /&#x?[^;]+;?/g
let charMatch
while ((charMatch = charRefPattern.exec(xml)) !== null) {
const ref = charMatch[0]
if (ref.startsWith("&#x")) {
if (!ref.endsWith(";")) {
return `Invalid XML: Missing semicolon after hex reference: ${ref}`
}
const hexDigits = ref.substring(3, ref.length - 1)
if (hexDigits.length === 0 || !/^[0-9a-fA-F]+$/.test(hexDigits)) {
return `Invalid XML: Invalid hex character reference: ${ref}`
}
} else if (ref.startsWith("&#")) {
if (!ref.endsWith(";")) {
return `Invalid XML: Missing semicolon after decimal reference: ${ref}`
}
const decDigits = ref.substring(2, ref.length - 1)
if (decDigits.length === 0 || !/^[0-9]+$/.test(decDigits)) {
return `Invalid XML: Invalid decimal character reference: ${ref}`
}
}
})
}
if (orphanedMxPoints.length > 0) {
return `Invalid XML: Found orphaned mxPoint elements in cells (${orphanedMxPoints.slice(0, 3).join(", ")}). mxPoint elements must either have an 'as' attribute (e.g., as="sourcePoint") or be inside <Array as="points">. For edge waypoints, use: <Array as="points"><mxPoint x="..." y="..."/></Array>. Please fix the mxPoint structure.`
// 7. Check for invalid comment syntax (-- inside comments)
const commentPattern = /<!--([\s\S]*?)-->/g
let commentMatch
while ((commentMatch = commentPattern.exec(xml)) !== null) {
if (/--/.test(commentMatch[1])) {
return "Invalid XML: Comment contains -- (double hyphen) which is not allowed"
}
}
// 8. Check for unescaped entity references and invalid entity names
const bareAmpPattern = /&(?!(?:lt|gt|amp|quot|apos|#))/g
if (bareAmpPattern.test(xmlWithoutComments)) {
return "Invalid XML: Found unescaped & character(s). Replace & with &amp;"
}
const invalidEntityPattern = /&([a-zA-Z][a-zA-Z0-9]*);/g
const validEntities = new Set(["lt", "gt", "amp", "quot", "apos"])
let entityMatch
while (
(entityMatch = invalidEntityPattern.exec(xmlWithoutComments)) !== null
) {
if (!validEntities.has(entityMatch[1])) {
return `Invalid XML: Invalid entity reference: &${entityMatch[1]}; - use only valid XML entities (lt, gt, amp, quot, apos)`
}
}
// 9. Check for empty id attributes on mxCell
if (/<mxCell[^>]*\sid\s*=\s*["']\s*["'][^>]*>/g.test(xml)) {
return "Invalid XML: Found mxCell element(s) with empty id attribute"
}
// 10. Check for mxfile wrapper (warning only - may not work with URL hash loading)
// Disabled: This is just a warning, not an error
// if (xml.trim().startsWith('<mxfile')) { ... }
// 11. Check for nested mxCell tags
const cellTagPattern = /<\/?mxCell[^>]*>/g
const cellStack: number[] = []
let cellMatch
while ((cellMatch = cellTagPattern.exec(xml)) !== null) {
const tag = cellMatch[0]
if (tag.startsWith("</mxCell>")) {
if (cellStack.length > 0) cellStack.pop()
} else if (!tag.endsWith("/>")) {
const isLabelOrGeometry =
/\sas\s*=\s*["'](valueLabel|geometry)["']/.test(tag)
if (!isLabelOrGeometry) {
cellStack.push(cellMatch.index)
if (cellStack.length > 1) {
return "Invalid XML: Found nested mxCell tags. Cells should be siblings, not nested inside other mxCell elements."
}
}
}
}
return null
}
/**
* Attempts to auto-fix common XML issues in draw.io diagrams
* @param xml - The XML string to fix
* @returns Object with fixed XML and list of fixes applied
*/
export function autoFixXml(xml: string): { fixed: string; fixes: string[] } {
let fixed = xml
const fixes: string[] = []
// 1. Remove CDATA wrapper
if (/^\s*<!\[CDATA\[/.test(fixed)) {
fixed = fixed.replace(/^\s*<!\[CDATA\[/, "").replace(/\]\]>\s*$/, "")
fixes.push("Removed CDATA wrapper")
}
// 2. Fix duplicate attributes (keep first occurrence, remove duplicates)
const structuralAttrsToFix = [
"edge",
"parent",
"source",
"target",
"vertex",
"connectable",
]
let dupAttrFixed = false
fixed = fixed.replace(/<[^>]+>/g, (tag) => {
const seenAttrs = new Set<string>()
let newTag = tag
for (const attr of structuralAttrsToFix) {
// Find all occurrences of this attribute
const attrRegex = new RegExp(
`\\s${attr}\\s*=\\s*["'][^"']*["']`,
"gi",
)
const matches = tag.match(attrRegex)
if (matches && matches.length > 1) {
// Keep first, remove others
let firstKept = false
newTag = newTag.replace(attrRegex, (m) => {
if (!firstKept) {
firstKept = true
return m
}
dupAttrFixed = true
return ""
})
}
}
return newTag
})
if (dupAttrFixed) {
fixes.push("Removed duplicate structural attributes")
}
// 3. Fix unescaped & characters (but not valid entities)
// Match & not followed by valid entity pattern
const ampersandPattern =
/&(?!(?:lt|gt|amp|quot|apos|#[0-9]+|#x[0-9a-fA-F]+);)/g
if (ampersandPattern.test(fixed)) {
fixed = fixed.replace(
/&(?!(?:lt|gt|amp|quot|apos|#[0-9]+|#x[0-9a-fA-F]+);)/g,
"&amp;",
)
fixes.push("Escaped unescaped & characters")
}
// 3. Fix invalid entity names like &ampquot; -> &quot;
// Common mistake: double-escaping
const invalidEntities = [
{ pattern: /&ampquot;/g, replacement: "&quot;", name: "&ampquot;" },
{ pattern: /&amplt;/g, replacement: "&lt;", name: "&amplt;" },
{ pattern: /&ampgt;/g, replacement: "&gt;", name: "&ampgt;" },
{ pattern: /&ampapos;/g, replacement: "&apos;", name: "&ampapos;" },
{ pattern: /&ampamp;/g, replacement: "&amp;", name: "&ampamp;" },
]
for (const { pattern, replacement, name } of invalidEntities) {
if (pattern.test(fixed)) {
fixed = fixed.replace(pattern, replacement)
fixes.push(`Fixed double-escaped entity ${name}`)
}
}
// 3b. Fix malformed attribute values where &quot; is used as delimiter
// Pattern: attr=&quot;value&quot; should be attr="&quot;value&quot;"
const malformedQuotePattern =
/(\s[a-zA-Z][a-zA-Z0-9_:-]*)=&quot;([^&]*(?:&(?!quot;)[^&]*)*)&quot;/g
if (malformedQuotePattern.test(fixed)) {
fixed = fixed.replace(
/(\s[a-zA-Z][a-zA-Z0-9_:-]*)=&quot;([^&]*(?:&(?!quot;)[^&]*)*)&quot;/g,
'$1="&quot;$2&quot;"',
)
fixes.push(
'Fixed malformed attribute quotes (=&quot;...&quot; to ="&quot;...&quot;")',
)
}
// 4. Fix unescaped < in attribute values
// This is tricky - we need to find < inside quoted attribute values
const attrPattern = /(=\s*")([^"]*?)(<)([^"]*?)(")/g
let attrMatch
let hasUnescapedLt = false
while ((attrMatch = attrPattern.exec(fixed)) !== null) {
if (!attrMatch[3].startsWith("&lt;")) {
hasUnescapedLt = true
break
}
}
if (hasUnescapedLt) {
// Replace < with &lt; inside attribute values
fixed = fixed.replace(/=\s*"([^"]*)"/g, (match, value) => {
const escaped = value.replace(/</g, "&lt;")
return `="${escaped}"`
})
fixes.push("Escaped < characters in attribute values")
}
// 5. Fix invalid character references (remove malformed ones)
// Pattern: &#x followed by non-hex chars before ;
const invalidHexRefs: string[] = []
fixed = fixed.replace(/&#x([^;]*);/g, (match, hex) => {
if (/^[0-9a-fA-F]+$/.test(hex) && hex.length > 0) {
return match // Valid hex ref, keep it
}
invalidHexRefs.push(match)
return "" // Remove invalid ref
})
if (invalidHexRefs.length > 0) {
fixes.push(
`Removed ${invalidHexRefs.length} invalid hex character reference(s)`,
)
}
// 6. Fix invalid decimal character references
const invalidDecRefs: string[] = []
fixed = fixed.replace(/&#([^x][^;]*);/g, (match, dec) => {
if (/^[0-9]+$/.test(dec) && dec.length > 0) {
return match // Valid decimal ref, keep it
}
invalidDecRefs.push(match)
return "" // Remove invalid ref
})
if (invalidDecRefs.length > 0) {
fixes.push(
`Removed ${invalidDecRefs.length} invalid decimal character reference(s)`,
)
}
// 7. Fix invalid comment syntax (replace -- with - repeatedly until none left)
fixed = fixed.replace(/<!--([\s\S]*?)-->/g, (match, content) => {
if (/--/.test(content)) {
// Keep replacing until no double hyphens remain
let fixedContent = content
while (/--/.test(fixedContent)) {
fixedContent = fixedContent.replace(/--/g, "-")
}
fixes.push("Fixed invalid comment syntax (removed double hyphens)")
return `<!--${fixedContent}-->`
}
return match
})
// 8. Fix <Cell> tags that should be <mxCell> (common LLM mistake)
// This handles both opening and closing tags
const hasCellTags = /<\/?Cell[\s>]/i.test(fixed)
if (hasCellTags) {
fixed = fixed.replace(/<Cell(\s)/gi, "<mxCell$1")
fixed = fixed.replace(/<Cell>/gi, "<mxCell>")
fixed = fixed.replace(/<\/Cell>/gi, "</mxCell>")
fixes.push("Fixed <Cell> tags to <mxCell>")
}
// 9. Fix common closing tag typos
const tagTypos = [
{ wrong: /<\/mxElement>/gi, right: "</mxCell>", name: "</mxElement>" },
{ wrong: /<\/mxcell>/g, right: "</mxCell>", name: "</mxcell>" }, // case sensitivity
{
wrong: /<\/mxgeometry>/g,
right: "</mxGeometry>",
name: "</mxgeometry>",
},
{ wrong: /<\/mxpoint>/g, right: "</mxPoint>", name: "</mxpoint>" },
{
wrong: /<\/mxgraphmodel>/gi,
right: "</mxGraphModel>",
name: "</mxgraphmodel>",
},
]
for (const { wrong, right, name } of tagTypos) {
if (wrong.test(fixed)) {
fixed = fixed.replace(wrong, right)
fixes.push(`Fixed typo ${name} to ${right}`)
}
}
// 10. Fix unclosed tags by appending missing closing tags
// Track open tags and close any that are left open using stateful parser
const tagStack: string[] = []
let idx = 0
while (idx < fixed.length) {
const tagStart = fixed.indexOf("<", idx)
if (tagStart === -1) break
// Find matching > by tracking quotes
let tagEnd = tagStart + 1
let inQuote = false
let quoteChar = ""
while (tagEnd < fixed.length) {
const c = fixed[tagEnd]
if (inQuote) {
if (c === quoteChar) inQuote = false
} else {
if (c === '"' || c === "'") {
inQuote = true
quoteChar = c
} else if (c === ">") {
break
}
}
tagEnd++
}
if (tagEnd >= fixed.length) break
const tag = fixed.substring(tagStart, tagEnd + 1)
idx = tagEnd + 1
const tagMatch2 = /^<(\/?)([a-zA-Z][a-zA-Z0-9:_-]*)/.exec(tag)
if (!tagMatch2) continue
const isClosing = tagMatch2[1] === "/"
const tagName = tagMatch2[2]
const isSelfClosing = tag.endsWith("/>")
if (isClosing) {
// Find matching opening tag (may not be the last one if there's mismatch)
const lastIdx = tagStack.lastIndexOf(tagName)
if (lastIdx !== -1) {
tagStack.splice(lastIdx, 1)
}
} else if (!isSelfClosing) {
tagStack.push(tagName)
}
}
// If there are unclosed tags, append closing tags in reverse order
// But first verify with simple count that they're actually unclosed
if (tagStack.length > 0) {
const tagsToClose: string[] = []
for (const tagName of tagStack.reverse()) {
// Simple count check: only close if opens > closes
const openCount = (
fixed.match(new RegExp(`<${tagName}[\\s>]`, "gi")) || []
).length
const closeCount = (
fixed.match(new RegExp(`</${tagName}>`, "gi")) || []
).length
if (openCount > closeCount) {
tagsToClose.push(tagName)
}
}
if (tagsToClose.length > 0) {
const closingTags = tagsToClose.map((t) => `</${t}>`).join("\n")
fixed = fixed.trimEnd() + "\n" + closingTags
fixes.push(
`Closed ${tagsToClose.length} unclosed tag(s): ${tagsToClose.join(", ")}`,
)
}
}
// 11. Fix nested mxCell by flattening
// Pattern A: <mxCell id="X">...<mxCell id="X">...</mxCell></mxCell> (duplicate ID)
// Pattern B: <mxCell id="X">...<mxCell id="Y">...</mxCell></mxCell> (different ID - true nesting)
const lines = fixed.split("\n")
let newLines: string[] = []
let nestedFixed = 0
let extraClosingToRemove = 0
// First pass: fix duplicate ID nesting (same as before)
for (let i = 0; i < lines.length; i++) {
const line = lines[i]
const nextLine = lines[i + 1]
// Check if current line and next line are both mxCell opening tags with same ID
if (
nextLine &&
/<mxCell\s/.test(line) &&
/<mxCell\s/.test(nextLine) &&
!line.includes("/>") &&
!nextLine.includes("/>")
) {
const id1 = line.match(/\bid\s*=\s*["']([^"']+)["']/)?.[1]
const id2 = nextLine.match(/\bid\s*=\s*["']([^"']+)["']/)?.[1]
if (id1 && id1 === id2) {
nestedFixed++
extraClosingToRemove++ // Need to remove one </mxCell> later
continue // Skip this duplicate opening line
}
}
// Remove extra </mxCell> if we have pending removals
if (extraClosingToRemove > 0 && /^\s*<\/mxCell>\s*$/.test(line)) {
extraClosingToRemove--
continue // Skip this closing tag
}
newLines.push(line)
}
if (nestedFixed > 0) {
fixed = newLines.join("\n")
fixes.push(`Flattened ${nestedFixed} duplicate-ID nested mxCell(s)`)
}
// Second pass: fix true nesting (different IDs)
// Insert </mxCell> before nested child to close parent
const lines2 = fixed.split("\n")
newLines = []
let trueNestedFixed = 0
let cellDepth = 0
let pendingCloseRemoval = 0
for (let i = 0; i < lines2.length; i++) {
const line = lines2[i]
const trimmed = line.trim()
// Track mxCell depth
const isOpenCell = /<mxCell\s/.test(trimmed) && !trimmed.endsWith("/>")
const isCloseCell = trimmed === "</mxCell>"
const isSelfClose = /<mxCell[^>]*\/>/.test(trimmed)
if (isOpenCell) {
if (cellDepth > 0) {
// Found nested cell - insert closing tag for parent before this line
const indent = line.match(/^(\s*)/)?.[1] || ""
newLines.push(indent + "</mxCell>")
trueNestedFixed++
pendingCloseRemoval++ // Need to remove one </mxCell> later
}
cellDepth = 1 // Reset to 1 since we just opened a new cell
newLines.push(line)
} else if (isCloseCell) {
if (pendingCloseRemoval > 0) {
pendingCloseRemoval--
// Skip this extra closing tag
} else {
cellDepth = Math.max(0, cellDepth - 1)
newLines.push(line)
}
} else {
newLines.push(line)
}
}
if (trueNestedFixed > 0) {
fixed = newLines.join("\n")
fixes.push(`Fixed ${trueNestedFixed} true nested mxCell(s)`)
}
// 12. Fix duplicate IDs by appending suffix
const idPattern = /\bid\s*=\s*["']([^"']+)["']/gi
const seenIds = new Map<string, number>()
const duplicateIds: string[] = []
// First pass: find duplicates
let idMatch
const tempPattern = /\bid\s*=\s*["']([^"']+)["']/gi
while ((idMatch = tempPattern.exec(fixed)) !== null) {
const id = idMatch[1]
seenIds.set(id, (seenIds.get(id) || 0) + 1)
}
// Find which IDs are duplicated
for (const [id, count] of seenIds) {
if (count > 1) duplicateIds.push(id)
}
// Second pass: rename duplicates (keep first occurrence, rename others)
if (duplicateIds.length > 0) {
const idCounters = new Map<string, number>()
fixed = fixed.replace(/\bid\s*=\s*["']([^"']+)["']/gi, (match, id) => {
if (!duplicateIds.includes(id)) return match
const count = idCounters.get(id) || 0
idCounters.set(id, count + 1)
if (count === 0) return match // Keep first occurrence
// Rename subsequent occurrences
const newId = `${id}_dup${count}`
return match.replace(id, newId)
})
fixes.push(`Renamed ${duplicateIds.length} duplicate ID(s)`)
}
// 9. Fix empty id attributes by generating unique IDs
let emptyIdCount = 0
fixed = fixed.replace(
/<mxCell([^>]*)\sid\s*=\s*["']\s*["']([^>]*)>/g,
(match, before, after) => {
emptyIdCount++
const newId = `cell_${Date.now()}_${emptyIdCount}`
return `<mxCell${before} id="${newId}"${after}>`
},
)
if (emptyIdCount > 0) {
fixes.push(`Generated ${emptyIdCount} missing ID(s)`)
}
return { fixed, fixes }
}
/**
* Validates XML and attempts to fix if invalid
* @param xml - The XML string to validate and potentially fix
* @returns Object with validation result, fixed XML if applicable, and fixes applied
*/
export function validateAndFixXml(xml: string): {
valid: boolean
error: string | null
fixed: string | null
fixes: string[]
} {
// First validation attempt
let error = validateMxCellStructure(xml)
if (!error) {
return { valid: true, error: null, fixed: null, fixes: [] }
}
// Try to fix
const { fixed, fixes } = autoFixXml(xml)
// Validate the fixed version
error = validateMxCellStructure(fixed)
if (!error) {
return { valid: true, error: null, fixed, fixes }
}
// Still invalid after fixes
return { valid: false, error, fixed: null, fixes }
}
export function extractDiagramXML(xml_svg_string: string): string {
try {
// 1. Parse the SVG string (using built-in DOMParser in a browser-like environment)