Allow for a small time in cache but then only revalidate

This should use caches a little but only fetch the whole config if it changed as for example in the test.

cypress/e2e/homepage_config.cy.js

@@ -0,0 +1,67 @@
+describe('Home page', function() {
+    const BASEX_ROOT = Cypress.env('BASEX_ROOT') || '/app/.heroku/basex'
+    const BASEX_PWD = Cypress.env('BASEX_admin_pw') || 'admin'
+
+	it('should show Tunisia with different config', function() {
+    	cy.exec(`${BASEX_ROOT}/bin/basexclient -Uadmin -P${BASEX_PWD} -c "OPEN vicav_projects; REPLACE vicav.xml ${Cypress.config()['fileServerFolder']}/fixtures/vicav_projects/map.xml"`)
+		cy.request({
+			method: 'PUT',
+			url: 'http://localhost:8984/vicav/project',
+			headers: {'Accept': 'application/json'}
+	    }).as('refreshConfig')
+		cy.get('@refreshConfig').should((response) => {
+			expect(response.status).to.equal(200)
+			expect(response.body.projectConfig).to.exist
+		})
+		cy.request({
+			method: 'GET',
+			url: 'http://localhost:8984/vicav/project',
+			headers: {'Accept': 'application/json'}
+	    }).as('config')
+		cy.get('@config').should((response) => {
+			expect(response.status).to.equal(200)
+			expect(response.body.projectConfig).to.exist
+			expect(response.body.projectConfig.cached).to.be.true
+			expect(response.body.ETag).to.exist
+			expect(response.headers['cache-control']).to.contain('max-age=2')
+			expect(response.headers['cache-control']).to.contain('must-revalidate')
+		})
+		cy.visit('http://localhost:8984/vicav/')
+		cy.get('#cookie-overlay').should('be.visible')
+		cy.get('.cookie-accept-btn').click()
+		cy.get('#cookie-overlay').should('not.be.visible')
+	    cy.get('img.leaflet-marker-icon') // Wait until the initial markers appear.
+	    cy.get('img[alt^="Khorasan"]').should('not.be.visible');
+		cy.wait(1000) // Wait for the cache to expire
+    })
+
+	it('should show whole Middle-East by deafult', function() {
+    	cy.exec(`${BASEX_ROOT}/bin/basexclient -Uadmin -P${BASEX_PWD} -c "OPEN vicav_projects; REPLACE vicav.xml ${Cypress.config()['fileServerFolder']}/fixtures/vicav_projects/vicav.xml"`)
+		cy.request({
+			method: 'PUT',
+			url: 'http://localhost:8984/vicav/project',
+			headers: {'Accept': 'application/json'}
+		}).as('refreshConfig')
+		cy.get('@refreshConfig').should((response) => {
+			expect(response.status).to.equal(200)
+			expect(response.body.projectConfig).to.exist
+		})
+		cy.request({
+			method: 'GET',
+			url: 'http://localhost:8984/vicav/project',
+			headers: {'Accept': 'application/json'}
+	    }).as('config')
+		cy.get('@config').should((response) => {
+			expect(response.status).to.equal(200)
+			expect(response.body.projectConfig).to.exist
+			expect(response.body.projectConfig.cached).to.be.true
+			expect(response.body.ETag).to.exist
+		})
+		cy.visit('http://localhost:8984/vicav/')
+		cy.get('#cookie-overlay').should('be.visible')
+		cy.get('.cookie-accept-btn').click()
+		cy.get('#cookie-overlay').should('not.be.visible')
+    	cy.get('img.leaflet-marker-icon') // Wait until the initial markers appear.
+		cy.get('img[alt^="Khorasan"]').should('be.visible');
+    })
+})

vicav.xqm

@@ -114,13 +114,13 @@ function vicav:project_config() {
     </problem>,
   map:merge((cors:header(()), vicav:return_content_header(), map{
       'X-UA-Compatible': 'IE=11'
-    , 'Cache-Control': 'max-age=3600,public'
+    , 'Cache-Control': 'public, max-age=2, must-revalidate'
     , 'ETag': $hash
     })))
   else api-problem:or_result (prof:current-ns(),
     vicav:_project_config#0, [], map:merge((cors:header(()), vicav:return_content_header(), map{
       'X-UA-Compatible': 'IE=11'
-    , 'Cache-Control': 'max-age=3600,public'
+    , 'Cache-Control': 'public, max-age=2, must-revalidate'
     , 'ETag': $hash
     }))
   )