DEPRECATED - now migrated to a package in the Koop monorepo. Update any npm usage to @koopjs/featureserver.
An open source implementation of the GeoServices specification
This is meant to be used as a plugin to Express
constexpress=require('express')constapp=express()// set up a basic express serverconstFeatureServer=require('featureserver')constcache=require('cache')// We only need one handler because FeatureServer.route is going to do all the workconsthandler=(req,res)=>{cache.get(/* some geojson */,(err,data)=>{if(err)res.status(500).json({error: err.message})elseFeatureServer.route(req,res,data)})}// Sets up all of the handled routes to support `GET` and `POST`constroutes=['/FeatureServer','/FeatureServer/layers','/FeatureServer/:layer','/FeatureServer/:layer/:method']routes.forEach(route=>{app.route(route).get(handler).post(handler)})FeatureServer allows several defaults to be set at runtime via Express's app.locals method. Specifically, you will need to set:
app.locals.config={featureServer: {// define default here}}If you are using FeatureServer as part of a Koop instance, the equivalent of Express's app.locals is koop.server.locals.
The follow properties can be set at runtime with the noted method:
app.locals.config={featureServer: {currentVersion: 11.01,// defaults to 10.51fullVersion: '11.0.1',// defaults to '10.5.1'serviceDescription: 'default service description',description: 'default layer description'}}- FeatureServer.route
- FeatureServer.query
- FeatureServer.serverInfo
- FeatureServer.layerInfo
- FeatureServer.layers
- FeatureServer.generateRenderer
- FeatureServer.authenticate
- FeatureServer.error.authorize
- FeatureServer.authenticate
- FeatureServer.queryRelatedRecords
Pass in an incoming request object, an outgoing response object, a geojson object, and options and this function will route and return a geoservices compliant response
- Supports: '/FeatureServer', '/FeatureServer/layers', '/FeatureServer/:layer', '/FeatureServer/:layer/:method'
- Note: only
query,info, andgenerateRendererare supported methods at this time.
- Note: only
FeatureServer.route(req,res,data,options)- data is either a geojson object extended with some additional properties or an object with a layers property which an array of extended geojson objects. These properties are optional and can be used to provide more specific metadata or to shortcut the built in filtering mechanism.
e.g.
{ type: 'FeatureCollection'// Static features: Array,// GeoJSON featuresstatistics: Object,// pass statistics to an outStatistics request to or else they will be calculated from geojson features passed inmetadata: {id: number,// The unique layer id. If supplied for one layer, you should supply for all layers to avoid multiple layers having the same id.name: String,// The name of the layerdescription: String,// The description of the layercopyrightText: String,// The copyright text (layer attribution text)extent: Array,// valid extent array e.g. [[180,90],[-180,-90]]displayField: String,// The display field to be used by a clientgeometryType: String// REQUIRED if no features are returned with this object Point || MultiPoint || LineString || MultiLineString || Polygon || MultiPolygonidField: String,// unique identifier field,maxRecordCount: Number,// the maximum number of features a provider can return at oncelimitExceeded: Boolean,// whether or not the server has limited the features returnedtimeInfo: Object,// describes the time extent and capabilities of the layer,transform: Object,// describes a quantization transformationrenderer: Object,// provider can over-ride default symbology of FeatureServer output with a renderer object. See https://developers.arcgis.com/web-map-specification/objects/simpleRenderer, for object specification.defaultVisibility: boolean,// The default visibility of this layerminScale: number,// The minScale value for this layermaxScale: number,// The maxScale value for this layerfields: [{// Subkeys are optionalname: String,type: String,// 'Date' || 'Double' || 'Integer' || 'String'alias: String,// how should clients display this field name,}]},capabilities: {quantization: Boolean// True if the provider supports quantization},filtersApplied: {all: Boolean// true if all post processing should be skippedgeometry: Boolean,// true if a geometric filter has already been applied to the datawhere: Boolean,// true if a sql-like where filter has already been applied to the dataoffset: Boolean// true if the result offset has already been applied to the data,limit: Boolean// true if the result count has already been limited,projection: Boolean// true if the result data has already been projected} count: Number// pass count if the number of features in a query has been pre-calculated}or
{layers: [{type: 'FeatureCollection'...},{type: 'FeatureCollection'...}]- options is an object that dictates method actions. See
FeatureServer.queryandFeatureServer.generateRendererfor more details.
Pass in geojson and options (a valid geoservices query object), and the function will perform the query and return a valid geoservices query object. The in addition to input statistics:{}, following is an example of all query options that can be passed into the query route: '/FeatureServer/:layer/query'
e.g.
constoptions={where: `1=1`,objectIds: '1,2,3',geometry: {xmin: -110,ymin: 30,xmax: -106,ymax: 50,spatialReference: {wkid: 4326},},geometryType: 'esriGeometryEnvelope',spatialRel: 'esriSpatialRelContains',outFields: '*',returnGeometry: true,outSR: 102100,// output spatial referencereturnIdsOnly: true,returnCountOnly: true,orderByFields: 'Full/Part_COUNT DESC',groupByFieldsForStatistics: 'Full/Part',outStatistics: {statisticType: 'count',onStatisticField: '<field>',outStatisticFieldName: 'name'},returnDistinctValues: true,resultOffset: 0,resultRecordCount: 0,f: 'pjson'}FeatureServer.query(geojson,options)Generate version 10.51 Geoservices server info
constserver={description: String// Describes the collection of layers below,copyrightText: String// Optional copyright textmaxRecordCount: Number// the maximum number of features a provider can return at once,hasStaticData: Boolean// whether or not the server contains any data that is not changinghasAttachments: Boolean// whether or not the server contains any attachments for this layerlayers: [{// A collection of all the layers managed by the servertype: 'FeatureCollection',metadata: {id: number,// The unique layer id. If supplied for one layer, you should supply for all layers to avoid multiple layers having the same id.name: String,// The name of the layerdescription: String,// The description of the layerextent: Array,// valid extent array e.g. [[180,90],[-180,-90]]displayField: String,// The display field to be used by a clientidField: String,// unique identifier field,geometryType: String,// REQUIRED if no features are returned with this object Point || MultiPoint || LineString || MultiLineString || Polygon || MultiPolygonmaxRecordCount: Number,// the maximum number of features a provider can return at oncelimitExceeded: Boolean,// whether or not the server has limited the features returnedtimeInfo: Object,// describes the time extent and capabilities of the layerrenderer: Object,// provider can over-ride default symbology of FeatureServer output with a renderer object. See https://developers.arcgis.com/web-map-specification/objects/simpleRenderer, for object specification.defaultVisibility: boolean,// The default visibility of this layerminScale: number,// The minScale value for this layermaxScale: number// The maxScale value for this layer}features: [// If all the metadata provided above is provided features are optional.{type: 'Feature',geometry: {type: 'Point',coordinates: [125.6,10.1]},properties: {name: 'Dinagat Islands'}}]}}],tables: [{// A collection of all the tables managed by the servertype: 'FeatureCollection',metadata: {// see layer metadata}}],relationships: [{// A collection of all relationships manged by the serverid: number,// The unique relationship id.name: String,// The name of the relationship}]}FeatureServer.serverInfo(server)Generate version 10.51 Geoservices information about a single layer
FeatureServer.layerInfo(geojson,options)Note that the layer info is modified with properties metadata and capabilites found at the top-level of the GeoJSON object.
| GeoJSON property | Layer info result |
|---|---|
metadata.id | overrides default |
metadata.name | overrides default |
metadata.description | overrides default |
metadata.geometryType | overrides value determined from data |
metadata.extent | overrides value determined from data |
metadata.timeInfo | overrides default |
metadata.maxRecordCount | overrides default (2000) |
metadata.displayField | overrides default (OBJECTID) |
metadata.objectIdField | overrides default (OBJECTID) |
metadata.hasStaticData | overrides default (false) |
metadata.hasAttachments | overrides default (false) |
metadata.renderer | overrides default |
metadata.defaultVisibility | overrides default |
metadata.minScale | overrides default |
metadata.maxScale | overrides default |
metadata.relationships | overrides default |
capabilities.extract | when set to true, Extract added to capabilites (e.g., capabilities: "Query,Extract") |
capabilities.quantization | when set to true, supportsCoordinatesQuantization: true |
This defined the server managed relationships for the layer
e.g.
constmetadata={//...relationships: [{// A collection of all relationships manged by the serverid: number,// The unique relationship id.name: String,// The name of the relationshiprelatedTableId: number,// Id of the layer/table related records are foundcardinality: String,// esriRelCardinalityOneToMany | esriRelCardinalityManyToManyrole: String,// esriRelRoleOrigin | esriRelRoleDestinationkeyField: String,// key field name in the related Table composite: Boolean// likely to false}]//...}Generate version 10.51 Geoservices information about one or many layers
Can pass a single geojson object or an array of geojson objects
FeatureServer.layers(geojson,options)Pass in geojson and options, and the function will return a valid generateRenderer object. Two classificationDef classification types are supported, classBreaksDef and uniqueValueDef.
classBreaksDef is used to classify numeric data based on a number of breaks and a statistical method. Features can also be normalized before being classified. uniqueValueDef is used to classify data based on a unique field(s). If classification breaks are not supplied through in statistics, they will be generated using classificationDef options. The output is a generateRenderer object.
In addition to class breaks as input statistics: [], the following is an example of all classBreaksDef options that can be passed into the generateRenderer route: '/FeatureServer/:layer/generateRenderer'
e.g.
constoptions={*'classificationDef': {*'type': 'classBreaksDef',*'classificationField': '<field1>',*'classificationMethod': 'esriClassifyEqualInterval'|'esriClassifyNaturalBreaks'|'esriClassifyQuantile'|'esriClassifyStandardDeviation',*'breakCount': 9,'normalizationType': 'esriNormalizeByField'|'esriNormalizeByLog'|'esriNormalizeByPercentOfTotal','normalizationField': '<field2>'// mandatory if 'normalizationType' === 'esriNormalizeByField''baseSymbol': {'type': 'esriSMS','style': 'esriSMSCircle','width': 2},'colorRamp': {'type': 'algorithmic','fromColor': [115,76,0,255],'toColor': [255,25,86,255],'algorithm': 'esriHSVAlgorithm'}},'where': '<field2> > 39'}FeatureServer.generateRender(geojson,options)*requiredOutput:
{type: 'classBreaks',field: '<field1>',classificationMethod: 'esriClassifyEqualInterval',minValue: 0,classBreakInfos: [{classMinValue: 0,classMaxValue: 5,label: '0-5',description: '',symbol: {type: 'esriSMS',style: 'esriSMSCircle',width: 2,color: [115,76,0]}},{classMinValue: 6,classMaxValue: 11,label: '6-11',description: '',symbol: {type: 'esriSMS',style: 'esriSMSCircle',width: 2,color: [156,67,0]}}, ... ]}The following is an example of all uniqueValueDef options that can be passed into the generateRenderer route: '/FeatureServer/:layer/generateRenderer'
e.g.
constoptions={*'classificationDef': {*'type': 'uniqueValueDef',*'uniqueValueFields': ['Genus', '<field2>', '<field3>'],*'fieldDelimiter': ',' 'baseSymbol':{ 'type': 'esriSMS', 'style': 'esriSMSCircle', 'width': 2}, 'colorRamp':{ 'type': 'algorithmic', 'fromColor': [115,76,0,255], 'toColor': [255,25,86,255], 'algorithm': 'esriHSVAlgorithm'}}, 'where': 'latitude>39' }FeatureServer.generateRender(geojson,options)*requiredOutput:
{type: 'uniqueValue',field1: 'Genus',field2: '',field3: '',fieldDelimiter: ', ',defaultSymbol: {},defaultLabel: '',uniqueValueInfos: [{value: 'MAGNOLIA',count: 5908,label: 'MAGNOLIA',description: '',symbol: {type: 'esriSMS',style: 'esriSMSCircle',width: 2,color: [115,76,0]}},{value: 'QUERCUS',count: 12105,label: 'QUERCUS',description: '',symbol: {type: 'esriSMS',style: 'esriSMSCircle',width: 2,color: [116,76,0]}}, ... ]Pass in an outgoing response object and an authentication success object and this function will route and return a formatted authentication success response.
FeatureServer.authenticate(res, auth, ssl = false) authis the result of a successful authentication attempt that returns a token and expiration timesslis a boolean flag indicating if token should always be passed back via HTTPS. Defaults tofalse
e.g.,
const auth ={"token":"elS39KU4bMmZQgMXDuswgA14vavIp4mfpiqcWSr0qM6q4dFguTnnHddWqbpK5Mc3HsCN8XghlwawUUYApOOcxKNyg_9WqTofChJXxxD058_rL1HZkM5PDhUOh9YYQn1K", "expires":1524508236322 } FeatureServer.authenticate(res, auth){"token":"elS39KU4bMmZQgMXDuswgA14vavIp4mfpiqcWSr0qM6q4dFguTnnHddWqbpK5Mc3HsCN8XghlwawUUYApOOcxKNyg_9WqTofChJXxxD058_rL1HZkM5PDhUOh9YYQn1K", "expires":1524508236322, ssl: false } Pass in an outgoing response object and this function will route and return a formattted authorization error.
FeatureServer.error.authorize(res){"error":{"code": 499, "message": "Token Required", "details": [] } } Pass in an outgoing response object and this function will route and return a formatted authentication error.
FeatureServer.error.authenticate(res){"error":{"code": 400, "message": "Unable to generate token.", "details": ["Invalid username or password."] } } Pass in geojson and options, and the function will return a valid queryRelatedRecords object. Required attributes within options are objectIds and relationshipId.
The geojson should be in the special FeatureCollection of FeatureCollections format to show the relationship between requested Features within the layer/table and the referenced relatinoship's features. e.g.
constgeojson={"type": "FeatureCollection","features": [// Array of FeatureCollections by objectId with the related records as features{"type": "FeatureCollection","properties": {"OBJECTID": 37},"features": [{"type": "Feature","geometry": {...},"properties": {...}}]}]}constoptions={objectIds: "37, 462",// comma separated string of object ids within the layer to get related records relationshipId: 4,// relationship Id of the server manged relationship of the layer, see FeatureServer.layerInfo}FeatureServer.queryRelatedRecords(geojson,options)Output:
{"geometryType": "esriGeometryPolygon","spatialReference": {"wkid": 4267},"fields": [{"name": "OBJECTID","type": "esriFieldTypeOID","alias": "OBJECTID"},{"name": "FIELD1","type": "esriFieldTypeString","alias": "FIELD1","length": 25}],"relatedRecordGroups": [{"objectId": 37,"relatedRecords": [{"attributes": {"OBJECTID": 5540,"FIELD1": "1000147595"},"geometry": {...}}]}]}
