packages/mermaid/src/diagrams/er/erRenderer.js
import * as graphlib from 'dagre-d3-es/src/graphlib/index.js';
import { line, curveBasis, select } from 'd3';
import { layout as dagreLayout } from 'dagre-d3-es/src/dagre/index.js';
import { getConfig } from '../../diagram-api/diagramAPI.js';
import { log } from '../../logger.js';
import utils from '../../utils.js';
import erMarkers from './erMarkers.js';
import { configureSvgSize } from '../../setupGraphViewbox.js';
import { parseGenericTypes } from '../common/common.js';
import { v5 as uuid5 } from 'uuid';
/** Regex used to remove chars from the entity name so the result can be used in an id */
const BAD_ID_CHARS_REGEXP = /[^\dA-Za-z](\W)*/g;
// Configuration
let conf = {};
// Map so we can look up the id of an entity based on the name
let entityNameIds = new Map();
/**
* Allows the top-level API module to inject config specific to this renderer, storing it in the
* local conf object. Note that generic config still needs to be retrieved using getConfig()
* imported from the config module
*
* @param cnf
*/
export const setConf = function (cnf) {
const keys = Object.keys(cnf);
for (const key of keys) {
conf[key] = cnf[key];
}
};
/**
* Draw attributes for an entity
*
* @param groupNode The svg group node for the entity
* @param entityTextNode The svg node for the entity label text
* @param attributes An array of attributes defined for the entity (each attribute has a type and a
* name)
* @returns {object} The bounding box of the entity, after attributes have been added. The bounding
* box has a .width and .height
*/
const drawAttributes = (groupNode, entityTextNode, attributes) => {
const heightPadding = conf.entityPadding / 3; // Padding internal to attribute boxes
const widthPadding = conf.entityPadding / 3; // Ditto
const attrFontSize = conf.fontSize * 0.85;
const labelBBox = entityTextNode.node().getBBox();
const attributeNodes = []; // Intermediate storage for attribute nodes created so that we can do a second pass
let hasKeyType = false;
let hasComment = false;
let maxTypeWidth = 0;
let maxNameWidth = 0;
let maxKeyWidth = 0;
let maxCommentWidth = 0;
let cumulativeHeight = labelBBox.height + heightPadding * 2;
let attrNum = 1;
// Check to see if any of the attributes has a key or a comment
attributes.forEach((item) => {
if (item.attributeKeyTypeList !== undefined && item.attributeKeyTypeList.length > 0) {
hasKeyType = true;
}
if (item.attributeComment !== undefined) {
hasComment = true;
}
});
attributes.forEach((item) => {
const attrPrefix = `${entityTextNode.node().id}-attr-${attrNum}`;
let nodeHeight = 0;
const attributeType = parseGenericTypes(item.attributeType);
// Add a text node for the attribute type
const typeNode = groupNode
.append('text')
.classed('er entityLabel', true)
.attr('id', `${attrPrefix}-type`)
.attr('x', 0)
.attr('y', 0)
.style('dominant-baseline', 'middle')
.style('text-anchor', 'left')
.style('font-family', getConfig().fontFamily)
.style('font-size', attrFontSize + 'px')
.text(attributeType);
// Add a text node for the attribute name
const nameNode = groupNode
.append('text')
.classed('er entityLabel', true)
.attr('id', `${attrPrefix}-name`)
.attr('x', 0)
.attr('y', 0)
.style('dominant-baseline', 'middle')
.style('text-anchor', 'left')
.style('font-family', getConfig().fontFamily)
.style('font-size', attrFontSize + 'px')
.text(item.attributeName);
const attributeNode = {};
attributeNode.tn = typeNode;
attributeNode.nn = nameNode;
const typeBBox = typeNode.node().getBBox();
const nameBBox = nameNode.node().getBBox();
maxTypeWidth = Math.max(maxTypeWidth, typeBBox.width);
maxNameWidth = Math.max(maxNameWidth, nameBBox.width);
nodeHeight = Math.max(typeBBox.height, nameBBox.height);
if (hasKeyType) {
const keyTypeNodeText =
item.attributeKeyTypeList !== undefined ? item.attributeKeyTypeList.join(',') : '';
const keyTypeNode = groupNode
.append('text')
.classed('er entityLabel', true)
.attr('id', `${attrPrefix}-key`)
.attr('x', 0)
.attr('y', 0)
.style('dominant-baseline', 'middle')
.style('text-anchor', 'left')
.style('font-family', getConfig().fontFamily)
.style('font-size', attrFontSize + 'px')
.text(keyTypeNodeText);
attributeNode.kn = keyTypeNode;
const keyTypeBBox = keyTypeNode.node().getBBox();
maxKeyWidth = Math.max(maxKeyWidth, keyTypeBBox.width);
nodeHeight = Math.max(nodeHeight, keyTypeBBox.height);
}
if (hasComment) {
const commentNode = groupNode
.append('text')
.classed('er entityLabel', true)
.attr('id', `${attrPrefix}-comment`)
.attr('x', 0)
.attr('y', 0)
.style('dominant-baseline', 'middle')
.style('text-anchor', 'left')
.style('font-family', getConfig().fontFamily)
.style('font-size', attrFontSize + 'px')
.text(item.attributeComment || '');
attributeNode.cn = commentNode;
const commentNodeBBox = commentNode.node().getBBox();
maxCommentWidth = Math.max(maxCommentWidth, commentNodeBBox.width);
nodeHeight = Math.max(nodeHeight, commentNodeBBox.height);
}
attributeNode.height = nodeHeight;
// Keep a reference to the nodes so that we can iterate through them later
attributeNodes.push(attributeNode);
cumulativeHeight += nodeHeight + heightPadding * 2;
attrNum += 1;
});
let widthPaddingFactor = 4;
if (hasKeyType) {
widthPaddingFactor += 2;
}
if (hasComment) {
widthPaddingFactor += 2;
}
const maxWidth = maxTypeWidth + maxNameWidth + maxKeyWidth + maxCommentWidth;
// Calculate the new bounding box of the overall entity, now that attributes have been added
const bBox = {
width: Math.max(
conf.minEntityWidth,
Math.max(
labelBBox.width + conf.entityPadding * 2,
maxWidth + widthPadding * widthPaddingFactor
)
),
height:
attributes.length > 0
? cumulativeHeight
: Math.max(conf.minEntityHeight, labelBBox.height + conf.entityPadding * 2),
};
if (attributes.length > 0) {
// There might be some spare width for padding out attributes if the entity name is very long
const spareColumnWidth = Math.max(
0,
(bBox.width - maxWidth - widthPadding * widthPaddingFactor) / (widthPaddingFactor / 2)
);
// Position the entity label near the top of the entity bounding box
entityTextNode.attr(
'transform',
'translate(' + bBox.width / 2 + ',' + (heightPadding + labelBBox.height / 2) + ')'
);
// Add rectangular boxes for the attribute types/names
let heightOffset = labelBBox.height + heightPadding * 2; // Start at the bottom of the entity label
let attribStyle = 'attributeBoxOdd'; // We will flip the style on alternate rows to achieve a banded effect
attributeNodes.forEach((attributeNode) => {
// Calculate the alignment y coordinate for the type/name of the attribute
const alignY = heightOffset + heightPadding + attributeNode.height / 2;
// Position the type attribute
attributeNode.tn.attr('transform', 'translate(' + widthPadding + ',' + alignY + ')');
// TODO Handle spareWidth in attr('width')
// Insert a rectangle for the type
const typeRect = groupNode
.insert('rect', '#' + attributeNode.tn.node().id)
.classed(`er ${attribStyle}`, true)
.attr('x', 0)
.attr('y', heightOffset)
.attr('width', maxTypeWidth + widthPadding * 2 + spareColumnWidth)
.attr('height', attributeNode.height + heightPadding * 2);
const nameXOffset = parseFloat(typeRect.attr('x')) + parseFloat(typeRect.attr('width'));
// Position the name attribute
attributeNode.nn.attr(
'transform',
'translate(' + (nameXOffset + widthPadding) + ',' + alignY + ')'
);
// Insert a rectangle for the name
const nameRect = groupNode
.insert('rect', '#' + attributeNode.nn.node().id)
.classed(`er ${attribStyle}`, true)
.attr('x', nameXOffset)
.attr('y', heightOffset)
.attr('width', maxNameWidth + widthPadding * 2 + spareColumnWidth)
.attr('height', attributeNode.height + heightPadding * 2);
let keyTypeAndCommentXOffset =
parseFloat(nameRect.attr('x')) + parseFloat(nameRect.attr('width'));
if (hasKeyType) {
// Position the key type attribute
attributeNode.kn.attr(
'transform',
'translate(' + (keyTypeAndCommentXOffset + widthPadding) + ',' + alignY + ')'
);
// Insert a rectangle for the key type
const keyTypeRect = groupNode
.insert('rect', '#' + attributeNode.kn.node().id)
.classed(`er ${attribStyle}`, true)
.attr('x', keyTypeAndCommentXOffset)
.attr('y', heightOffset)
.attr('width', maxKeyWidth + widthPadding * 2 + spareColumnWidth)
.attr('height', attributeNode.height + heightPadding * 2);
keyTypeAndCommentXOffset =
parseFloat(keyTypeRect.attr('x')) + parseFloat(keyTypeRect.attr('width'));
}
if (hasComment) {
// Position the comment attribute
attributeNode.cn.attr(
'transform',
'translate(' + (keyTypeAndCommentXOffset + widthPadding) + ',' + alignY + ')'
);
// Insert a rectangle for the comment
groupNode
.insert('rect', '#' + attributeNode.cn.node().id)
.classed(`er ${attribStyle}`, 'true')
.attr('x', keyTypeAndCommentXOffset)
.attr('y', heightOffset)
.attr('width', maxCommentWidth + widthPadding * 2 + spareColumnWidth)
.attr('height', attributeNode.height + heightPadding * 2);
}
// Increment the height offset to move to the next row
heightOffset += attributeNode.height + heightPadding * 2;
// Flip the attribute style for row banding
attribStyle = attribStyle === 'attributeBoxOdd' ? 'attributeBoxEven' : 'attributeBoxOdd';
});
} else {
// Ensure the entity box is a decent size without any attributes
bBox.height = Math.max(conf.minEntityHeight, cumulativeHeight);
// Position the entity label in the middle of the box
entityTextNode.attr('transform', 'translate(' + bBox.width / 2 + ',' + bBox.height / 2 + ')');
}
return bBox;
};
/**
* Use D3 to construct the svg elements for the entities
*
* @param svgNode The svg node that contains the diagram
* @param entities The entities to be drawn
* @param graph The graph that contains the vertex and edge definitions post-layout
* @returns {object} The first entity that was inserted
*/
const drawEntities = function (svgNode, entities, graph) {
const keys = Object.keys(entities);
let firstOne;
keys.forEach(function (entityName) {
const entityId = generateId(entityName, 'entity');
entityNameIds.set(entityName, entityId);
// Create a group for each entity
const groupNode = svgNode.append('g').attr('id', entityId);
firstOne = firstOne === undefined ? entityId : firstOne;
// Label the entity - this is done first so that we can get the bounding box
// which then determines the size of the rectangle
const textId = 'text-' + entityId;
const textNode = groupNode
.append('text')
.classed('er entityLabel', true)
.attr('id', textId)
.attr('x', 0)
.attr('y', 0)
.style('dominant-baseline', 'middle')
.style('text-anchor', 'middle')
.style('font-family', getConfig().fontFamily)
.style('font-size', conf.fontSize + 'px')
.text(entities[entityName].alias ?? entityName);
const { width: entityWidth, height: entityHeight } = drawAttributes(
groupNode,
textNode,
entities[entityName].attributes
);
// Draw the rectangle - insert it before the text so that the text is not obscured
const rectNode = groupNode
.insert('rect', '#' + textId)
.classed('er entityBox', true)
.attr('x', 0)
.attr('y', 0)
.attr('width', entityWidth)
.attr('height', entityHeight);
const rectBBox = rectNode.node().getBBox();
// Add the entity to the graph using the entityId
graph.setNode(entityId, {
width: rectBBox.width,
height: rectBBox.height,
shape: 'rect',
id: entityId,
});
});
return firstOne;
}; // drawEntities
const adjustEntities = function (svgNode, graph) {
graph.nodes().forEach(function (v) {
if (v !== undefined && graph.node(v) !== undefined) {
svgNode
.select('#' + v)
.attr(
'transform',
'translate(' +
(graph.node(v).x - graph.node(v).width / 2) +
',' +
(graph.node(v).y - graph.node(v).height / 2) +
' )'
);
}
});
};
/**
* Construct a name for an edge based on the names of the 2 entities and the role (relationship)
* between them. Remove any spaces from it
*
* @param rel - A (parsed) relationship (e.g. one of the objects in the list returned by
* erDb.getRelationships)
* @returns {string}
*/
const getEdgeName = function (rel) {
return (rel.entityA + rel.roleA + rel.entityB).replace(/\s/g, '');
};
/**
* Add each relationship to the graph
*
* @param relationships The relationships to be added
* @param g The graph
* @returns {Array} The array of relationships
*/
const addRelationships = function (relationships, g) {
relationships.forEach(function (r) {
g.setEdge(
entityNameIds.get(r.entityA),
entityNameIds.get(r.entityB),
{ relationship: r },
getEdgeName(r)
);
});
return relationships;
}; // addRelationships
let relCnt = 0;
/**
* Draw a relationship using edge information from the graph
*
* @param svg The svg node
* @param rel The relationship to draw in the svg
* @param g The graph containing the edge information
* @param insert The insertion point in the svg DOM (because relationships have markers that need to
* sit 'behind' opaque entity boxes)
* @param diagObj
*/
const drawRelationshipFromLayout = function (svg, rel, g, insert, diagObj) {
relCnt++;
// Find the edge relating to this relationship
const edge = g.edge(
entityNameIds.get(rel.entityA),
entityNameIds.get(rel.entityB),
getEdgeName(rel)
);
// Get a function that will generate the line path
const lineFunction = line()
.x(function (d) {
return d.x;
})
.y(function (d) {
return d.y;
})
.curve(curveBasis);
// Insert the line at the right place
const svgPath = svg
.insert('path', '#' + insert)
.classed('er relationshipLine', true)
.attr('d', lineFunction(edge.points))
.style('stroke', conf.stroke)
.style('fill', 'none');
// ...and with dashes if necessary
if (rel.relSpec.relType === diagObj.db.Identification.NON_IDENTIFYING) {
svgPath.attr('stroke-dasharray', '8,8');
}
// TODO: Understand this better
let url = '';
if (conf.arrowMarkerAbsolute) {
url =
window.location.protocol +
'//' +
window.location.host +
window.location.pathname +
window.location.search;
url = url.replace(/\(/g, '\\(');
url = url.replace(/\)/g, '\\)');
}
// Decide which start and end markers it needs. It may be possible to be more concise here
// by reversing a start marker to make an end marker...but this will do for now
// Note that the 'A' entity's marker is at the end of the relationship and the 'B' entity's marker is at the start
switch (rel.relSpec.cardA) {
case diagObj.db.Cardinality.ZERO_OR_ONE:
svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.ZERO_OR_ONE_END + ')');
break;
case diagObj.db.Cardinality.ZERO_OR_MORE:
svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.ZERO_OR_MORE_END + ')');
break;
case diagObj.db.Cardinality.ONE_OR_MORE:
svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.ONE_OR_MORE_END + ')');
break;
case diagObj.db.Cardinality.ONLY_ONE:
svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.ONLY_ONE_END + ')');
break;
case diagObj.db.Cardinality.MD_PARENT:
svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.MD_PARENT_END + ')');
break;
}
switch (rel.relSpec.cardB) {
case diagObj.db.Cardinality.ZERO_OR_ONE:
svgPath.attr(
'marker-start',
'url(' + url + '#' + erMarkers.ERMarkers.ZERO_OR_ONE_START + ')'
);
break;
case diagObj.db.Cardinality.ZERO_OR_MORE:
svgPath.attr(
'marker-start',
'url(' + url + '#' + erMarkers.ERMarkers.ZERO_OR_MORE_START + ')'
);
break;
case diagObj.db.Cardinality.ONE_OR_MORE:
svgPath.attr(
'marker-start',
'url(' + url + '#' + erMarkers.ERMarkers.ONE_OR_MORE_START + ')'
);
break;
case diagObj.db.Cardinality.ONLY_ONE:
svgPath.attr('marker-start', 'url(' + url + '#' + erMarkers.ERMarkers.ONLY_ONE_START + ')');
break;
case diagObj.db.Cardinality.MD_PARENT:
svgPath.attr('marker-start', 'url(' + url + '#' + erMarkers.ERMarkers.MD_PARENT_START + ')');
break;
}
// Now label the relationship
// Find the half-way point
const len = svgPath.node().getTotalLength();
const labelPoint = svgPath.node().getPointAtLength(len * 0.5);
// Append a text node containing the label
const labelId = 'rel' + relCnt;
const labelNode = svg
.append('text')
.classed('er relationshipLabel', true)
.attr('id', labelId)
.attr('x', labelPoint.x)
.attr('y', labelPoint.y)
.style('text-anchor', 'middle')
.style('dominant-baseline', 'middle')
.style('font-family', getConfig().fontFamily)
.style('font-size', conf.fontSize + 'px')
.text(rel.roleA);
// Figure out how big the opaque 'container' rectangle needs to be
const labelBBox = labelNode.node().getBBox();
// Insert the opaque rectangle before the text label
svg
.insert('rect', '#' + labelId)
.classed('er relationshipLabelBox', true)
.attr('x', labelPoint.x - labelBBox.width / 2)
.attr('y', labelPoint.y - labelBBox.height / 2)
.attr('width', labelBBox.width)
.attr('height', labelBBox.height);
};
/**
* Draw en E-R diagram in the tag with id: id based on the text definition of the diagram
*
* @param text The text of the diagram
* @param id The unique id of the DOM node that contains the diagram
* @param _version
* @param diagObj
*/
export const draw = function (text, id, _version, diagObj) {
conf = getConfig().er;
log.info('Drawing ER diagram');
const securityLevel = getConfig().securityLevel;
// Handle root and Document for when rendering in sandbox mode
let sandboxElement;
if (securityLevel === 'sandbox') {
sandboxElement = select('#i' + id);
}
const root =
securityLevel === 'sandbox'
? select(sandboxElement.nodes()[0].contentDocument.body)
: select('body');
// const doc = securityLevel === 'sandbox' ? sandboxElement.nodes()[0].contentDocument : document;
// Get a reference to the svg node that contains the text
const svg = root.select(`[id='${id}']`);
// Add cardinality marker definitions to the svg
erMarkers.insertMarkers(svg, conf);
// Now we have to construct the diagram in a specific way:
// ---
// 1. Create all the entities in the svg node at 0,0, but with the correct dimensions (allowing for text content)
// 2. Make sure they are all added to the graph
// 3. Add all the edges (relationships) to the graph as well
// 4. Let dagre do its magic to lay out the graph. This assigns:
// - the centre coordinates for each node, bearing in mind the dimensions and edge relationships
// - the path coordinates for each edge
// But it has no impact on the svg child nodes - the diagram remains with every entity rooted at 0,0
// 5. Now assign a transform to each entity in the svg node so that it gets drawn in the correct place, as determined by
// its centre point, which is obtained from the graph, and it's width and height
// 6. And finally, create all the edges in the svg node using information from the graph
// ---
// Create the graph
let g;
// TODO: Explore directed vs undirected graphs, and how the layout is affected
// An E-R diagram could be said to be undirected, but there is merit in setting
// the direction from parent to child in a one-to-many as this influences graphlib to
// put the parent above the child (does it?), which is intuitive. Most relationships
// in ER diagrams are one-to-many.
g = new graphlib.Graph({
multigraph: true,
directed: true,
compound: false,
})
.setGraph({
rankdir: conf.layoutDirection,
marginx: 20,
marginy: 20,
nodesep: 100,
edgesep: 100,
ranksep: 100,
})
.setDefaultEdgeLabel(function () {
return {};
});
// Draw the entities (at 0,0), returning the first svg node that got
// inserted - this represents the insertion point for relationship paths
const firstEntity = drawEntities(svg, diagObj.db.getEntities(), g);
// TODO: externalize the addition of entities to the graph - it's a bit 'buried' in the above
// Add all the relationships to the graph
const relationships = addRelationships(diagObj.db.getRelationships(), g);
dagreLayout(g); // Node and edge positions will be updated
// Adjust the positions of the entities so that they adhere to the layout
adjustEntities(svg, g);
// Draw the relationships
relationships.forEach(function (rel) {
drawRelationshipFromLayout(svg, rel, g, firstEntity, diagObj);
});
const padding = conf.diagramPadding;
utils.insertTitle(svg, 'entityTitleText', conf.titleTopMargin, diagObj.db.getDiagramTitle());
const svgBounds = svg.node().getBBox();
const width = svgBounds.width + padding * 2;
const height = svgBounds.height + padding * 2;
configureSvgSize(svg, height, width, conf.useMaxWidth);
svg.attr('viewBox', `${svgBounds.x - padding} ${svgBounds.y - padding} ${width} ${height}`);
}; // draw
/**
* UUID namespace for ER diagram IDs
*
* This can be generated via running:
*
* ```js
* const { v5: uuid5 } = await import('uuid');
* uuid5(
* 'https://mermaid-js.github.io/mermaid/syntax/entityRelationshipDiagram.html',
* uuid5.URL
* );
* ```
*/
const MERMAID_ERDIAGRAM_UUID = '28e9f9db-3c8d-5aa5-9faf-44286ae5937c';
/**
* Return a unique id based on the given string. Start with the prefix, then a hyphen, then the
* simplified str, then a hyphen, then a unique uuid based on the str. (Hyphens are only included if needed.)
* Although the official XML standard for ids says that many more characters are valid in the id,
* this keeps things simple by accepting only A-Za-z0-9.
*
* @param {string} str Given string to use as the basis for the id. Default is `''`
* @param {string} prefix String to put at the start, followed by '-'. Default is `''`
* @returns {string}
* @see https://www.w3.org/TR/xml/#NT-Name
*/
export function generateId(str = '', prefix = '') {
const simplifiedStr = str.replace(BAD_ID_CHARS_REGEXP, '');
// we use `uuid v5` so that UUIDs are consistent given a string.
return `${strWithHyphen(prefix)}${strWithHyphen(simplifiedStr)}${uuid5(
str,
MERMAID_ERDIAGRAM_UUID
)}`;
}
/**
* Append a hyphen to a string only if the string isn't empty
*
* @param {string} str
* @returns {string}
* @todo This could be moved into a string utility file/class.
*/
function strWithHyphen(str = '') {
return str.length > 0 ? `${str}-` : '';
}
export default {
setConf,
draw,
};