org.exoplatform.caldav.service.CaldavRelayService

@Service public class CaldavRelayService extends Object

The server-side DAV relay: the browser addresses declared CalDAV servers through /caldav/rest/dav/{serverId}/** and this service forwards each request to the one host the registry row names, injecting the connected user's stored credentials. This is the piece that removes every reason for the browser to hold a CalDAV password or to reach a CalDAV origin directly, and it holds the whole security posture of the relay:

SSRF boundary — the target host comes only from the administrator-managed registry (CaldavServerService); the client chooses a serverId and a path on that host, never a URL. An unknown, inactive or non-registry target is refused, not forwarded, and the refusal happens before any socket is opened.
Credential custody — the credentials are produced by the provider the server row is configured with (CaldavCredentialsResolver) and injected here, never assembled from anything this class holds; any Authorization or Cookie header the browser sends is dropped. Nothing auth-shaped is ever logged. The one exception is probeAccount, which tries a credential pair typed in the connect drawer — material no provider can produce, because nothing stores it yet.
Method and header allow-lists — only the DAV verbs and headers the shipped connector actually issues pass through; everything else is attack surface and is refused or dropped.
Per-server namespace — responses advertise hrefs rooted at the upstream host's own path space (BlueMind roots everything at /dav/); they are rewritten under the relay prefix of that one server, so two servers can both advertise /dav/ without colliding — the collision a dev rig previously papered over with nginx sub_filter.

Field Summary

Fields

Modifier and Type

Field

Description

static final Set<String>

ALLOWED_METHODS

The DAV verbs the relay forwards: exactly what the shipped browser connector issues — PROPFIND (discovery, calendar and ETag listings), REPORT (calendar-query/multiget reads), GET (single-object read before a conditional write), PUT (create/update of an ICS object), DELETE (object removal), MKCALENDAR (mirror-calendar creation) — plus OPTIONS and HEAD, read-only capability probes some clients open with.

static final String

INVALID_PATH_MESSAGE

Message code for a relay path that is not a plain DAV resource path.

static final String

METHOD_NOT_ALLOWED_MESSAGE

Message code for a relay request naming a method outside the allow-list.

static final String

NOT_CONNECTED_MESSAGE

Message code for a user with no stored CalDAV credentials.

static final String

PROBE_CREDENTIALS_MESSAGE

Message code for a probe request missing its credentials.

static final String

RELAY_CODE_HEADER

Response header carrying the relay's own machine-readable outcome code, so the browser can tell a relay refusal (or a translated upstream credential rejection) from the same status genuinely answered by the upstream server, which always arrives without this header.

static final String

RESPONSE_TOO_LARGE_MESSAGE

Message code for an upstream response larger than the configured cap.

static final String

SERVER_INACTIVE_MESSAGE

Message code for a target server declared but deactivated.

static final String

SERVER_MISMATCH_MESSAGE

Message code for a target that is not the server the account is connected to.
Constructor Summary

Constructors

Constructor

Description

CaldavRelayService()
Method Summary

Modifier and Type

Method

Description

long

getMaxBodyBytes()

The size cap applied to request and response bodies alike, so the REST layer can refuse an oversized upload with the same limit this service enforces on downloads.

org.exoplatform.caldav.model.CaldavProbeResult

probeAccount(Long serverId, String username, String password)

Probes a CalDAV account server-side, before anything is stored: the connect drawer sends the typed credentials once, here, instead of the browser probing the CalDAV origin directly — which BlueMind's missing CORS headers made impossible without an nginx front.

org.exoplatform.caldav.model.CaldavRelayedResponse

relay(org.exoplatform.caldav.model.CaldavRelayRequest relayRequest)

Relays one DAV request of a connected user to the declared server it targets.

protected String

rewriteHrefs(String xml, URI upstreamBase, String relayPrefix)

Rewrites every DAV href of a multistatus body into relay space, so that the URL space the browser sees is closed under the relay: any href a response advertises — BlueMind's /dav/-rooted ones included — resolves back under /caldav/rest/dav/{serverId}/ instead of escaping to the platform root, which is the exact bug class that produced "cannot find homeUrl" against BlueMind when hrefs resolved against the wrong base.

protected String

rewriteHrefValue(String value, URI upstreamBase, String relayPrefix)

Rewrites one href value into relay space: a path-rooted href is prefixed, an absolute URL naming the upstream host is folded onto the prefix, and anything else — notably an absolute URL naming a foreign host — is left untouched, because rewriting it would turn the relay into an open proxy toward hosts no administrator declared.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details
- METHOD_NOT_ALLOWED_MESSAGE
  
  public static final String METHOD_NOT_ALLOWED_MESSAGE
  
  Message code for a relay request naming a method outside the allow-list.
  See Also:
  
  Constant Field Values
- INVALID_PATH_MESSAGE
  
  public static final String INVALID_PATH_MESSAGE
  
  Message code for a relay path that is not a plain DAV resource path.
  See Also:
  
  Constant Field Values
- NOT_CONNECTED_MESSAGE
  
  public static final String NOT_CONNECTED_MESSAGE
  
  Message code for a user with no stored CalDAV credentials.
  See Also:
  
  Constant Field Values
- SERVER_INACTIVE_MESSAGE
  
  public static final String SERVER_INACTIVE_MESSAGE
  
  Message code for a target server declared but deactivated.
  See Also:
  
  Constant Field Values
- SERVER_MISMATCH_MESSAGE
  
  public static final String SERVER_MISMATCH_MESSAGE
  
  Message code for a target that is not the server the account is connected to.
  See Also:
  
  Constant Field Values
- RESPONSE_TOO_LARGE_MESSAGE
  
  public static final String RESPONSE_TOO_LARGE_MESSAGE
  
  Message code for an upstream response larger than the configured cap.
  See Also:
  
  Constant Field Values
- PROBE_CREDENTIALS_MESSAGE
  
  public static final String PROBE_CREDENTIALS_MESSAGE
  
  Message code for a probe request missing its credentials.
  See Also:
  
  Constant Field Values
- RELAY_CODE_HEADER
  
  public static final String RELAY_CODE_HEADER
  
  Response header carrying the relay's own machine-readable outcome code, so the browser can tell a relay refusal (or a translated upstream credential rejection) from the same status genuinely answered by the upstream server, which always arrives without this header.
  See Also:
  
  Constant Field Values
- ALLOWED_METHODS
  
  public static final Set<String> ALLOWED_METHODS
  
  The DAV verbs the relay forwards: exactly what the shipped browser connector issues — PROPFIND (discovery, calendar and ETag listings), REPORT (calendar-query/multiget reads), GET (single-object read before a conditional write), PUT (create/update of an ICS object), DELETE (object removal), MKCALENDAR (mirror-calendar creation) — plus OPTIONS and HEAD, read-only capability probes some clients open with. Deliberately absent: PROPPATCH, POST, COPY, MOVE, LOCK, UNLOCK, MKCOL — no current flow sends them, so relaying them would be pure attack surface; the sync engine that may need PROPPATCH later talks to servers directly, not through this relay.
  Public because it is the single source of truth two gates read: this service's own 405 refusal, and the webapp's Spring Security StrictHttpFirewall, whose allowed-method list is built as standard-HTTP ∪ this set (CaldavHttpFirewallConfiguration) — the firewall would otherwise reject every DAV verb as a 400 before the dispatcher ever saw it. Sharing the constant means a verb added here is automatically admitted by the firewall, and a verb only the firewall admits (the standard ones the admin REST needs) still meets this service's 405 on the relay path.
Constructor Details
- CaldavRelayService
  
  public CaldavRelayService()
Method Details
- getMaxBodyBytes
  
  public long getMaxBodyBytes()
  
  The size cap applied to request and response bodies alike, so the REST layer can refuse an oversized upload with the same limit this service enforces on downloads.
  
  Returns:
  
  the cap in bytes
- relay
  
  public org.exoplatform.caldav.model.CaldavRelayedResponse relay(org.exoplatform.caldav.model.CaldavRelayRequest relayRequest) throws org.exoplatform.commons.exception.ObjectNotFoundException, IllegalAccessException
  
  Relays one DAV request of a connected user to the declared server it targets. The target host comes exclusively from the registry row — refused before any I/O when the row is unknown (ObjectNotFoundException), deactivated, or not the server the user's account is connected to (IllegalAccessException) — and the stored credentials of the user are injected as Basic auth. Upstream statuses pass through untouched so the browser connector's own DAV logic (207 parsing, 412 conflicts, BlueMind's 500-for-absent-object quirk) keeps holding, with one translation: an upstream 401/407 means the stored credentials are stale, so it becomes a 403 carrying caldav.error.credentials in the "x-caldav-relay-code" header, never a 401 the platform or the browser could read as an eXo authentication failure.
  
  Parameters:
  
  relayRequest - the request to relay, target named by serverId only
  
  Returns:
  
  the upstream response, headers allow-listed, hrefs rewritten
  
  Throws:
  
  org.exoplatform.commons.exception.ObjectNotFoundException - when no registration carries the id
  
  IllegalAccessException - when the server is deactivated or is not the one the user's account is connected to
  
  IllegalStateException - when the user has no stored credentials
  
  IllegalArgumentException - when the method is outside the allow-list or the path is not a plain DAV resource path
- probeAccount
  
  public org.exoplatform.caldav.model.CaldavProbeResult probeAccount(Long serverId, String username, String password) throws org.exoplatform.commons.exception.ObjectNotFoundException, IllegalAccessException
  
  Probes a CalDAV account server-side, before anything is stored: the connect drawer sends the typed credentials once, here, instead of the browser probing the CalDAV origin directly — which BlueMind's missing CORS headers made impossible without an nginx front. The probe is a Depth:0 PROPFIND against the declared server's own URL and classifies the answer with the same stable codes the browser probe historically produced. It never stores anything and injects nothing from the user's stored setting: only the typed credentials are tried, only against a registry row.
  This is the one request a refused connection makes — the drawer stores nothing until this says yes — so it is also the only place a refused connection can be heard from. Every outcome but acceptance is therefore written down here, exactly once per attempt: at warning when somebody other than the person typing has to act (the server unreachable, or answering as something that is not a calendar), at debug when they do not (their own username or password refused, which the drawer already tells them in words). A gateway status is classified as unreachable rather than as "not a CalDAV calendar": a 502 in front of a banned or stopped server used to tell the user their administrator had configured the wrong address (EXO-89806).
  
  Parameters:
  
  serverId - identifier of the declared server, or null for the resolution fallback (the seed registration)
  
  username - account username to try
  
  password - account password to try
  
  Returns:
  
  the classified outcome, never null
  
  Throws:
  
  org.exoplatform.commons.exception.ObjectNotFoundException - when no registration resolves
  
  IllegalAccessException - when the resolved server is deactivated
  
  IllegalArgumentException - when the credentials are blank or the username cannot be part of a URL path
- rewriteHrefs
  
  protected String rewriteHrefs(String xml, URI upstreamBase, String relayPrefix)
  
  Rewrites every DAV href of a multistatus body into relay space, so that the URL space the browser sees is closed under the relay: any href a response advertises — BlueMind's /dav/-rooted ones included — resolves back under /caldav/rest/dav/{serverId}/ instead of escaping to the platform root, which is the exact bug class that produced "cannot find homeUrl" against BlueMind when hrefs resolved against the wrong base.
  
  Parameters:
  
  xml - the multistatus body
  
  upstreamBase - the upstream base URI, for absolute-href matching
  
  relayPrefix - the relay prefix to root hrefs at
  
  Returns:
  
  the body with every rewritable href moved into relay space
- rewriteHrefValue
  
  protected String rewriteHrefValue(String value, URI upstreamBase, String relayPrefix)
  
  Rewrites one href value into relay space: a path-rooted href is prefixed, an absolute URL naming the upstream host is folded onto the prefix, and anything else — notably an absolute URL naming a foreign host — is left untouched, because rewriting it would turn the relay into an open proxy toward hosts no administrator declared.
  
  Parameters:
  
  value - the href text, possibly percent-encoded
  
  upstreamBase - the upstream base URI
  
  relayPrefix - the relay prefix to root the href at
  
  Returns:
  
  the rewritten href, or the value unchanged

Class CaldavRelayService

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Details

METHOD_NOT_ALLOWED_MESSAGE

INVALID_PATH_MESSAGE

NOT_CONNECTED_MESSAGE

SERVER_INACTIVE_MESSAGE

SERVER_MISMATCH_MESSAGE

RESPONSE_TOO_LARGE_MESSAGE

PROBE_CREDENTIALS_MESSAGE

RELAY_CODE_HEADER

ALLOWED_METHODS

Constructor Details

CaldavRelayService

Method Details

getMaxBodyBytes

relay

probeAccount

rewriteHrefs

rewriteHrefValue