.. Licensed under the Apache License, Version 2.0 (the "License"); you may not .. use this file except in compliance with the License. You may obtain a copy of .. the License at .. .. http://www.apache.org/licenses/LICENSE-2.0 .. .. Unless required by applicable law or agreed to in writing, software .. distributed under the License is distributed on an "AS IS" BASIS, WITHOUT .. WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the .. License for the specific language governing permissions and limitations under .. the License. .. default-domain:: config .. highlight:: ini =================== CouchDB HTTP Server =================== .. _config/httpd: HTTP Server Options =================== .. config:section:: chttpd :: Clustered HTTP Server Options .. note:: In CouchDB 2.x and 3.x, the `chttpd` section refers to the standard, clustered port. All use of CouchDB, aside from a few specific maintenance tasks as described in this documentation, should be performed over this port. .. config:option:: bind_address :: HTTP port IP address binding Defines the IP address by which the clustered port is available:: [chttpd] bind_address = 127.0.0.1 To let CouchDB listen any available IP address, use ``0.0.0.0``:: [chttpd] bind_address = 0.0.0.0 For IPv6 support you need to set ``::1`` if you want to let CouchDB listen correctly:: [chttpd] bind_address = ::1 or ``::`` for any available:: [chttpd] bind_address = :: .. config:option:: port :: Listen port Defines the port number to listen:: [chttpd] port = 5984 To let CouchDB use any free port, set this option to ``0``:: [chttpd] port = 0 .. config:option:: prefer_minimal :: Sends minimal set of headers If a request has the header ``"Prefer": "return=minimal"``, CouchDB will only send the headers that are listed for the ``prefer_minimal`` configuration.:: [chttpd] prefer_minimal = Cache-Control, Content-Length, Content-Range, Content-Type, ETag, Server, Transfer-Encoding, Vary .. warning:: Removing the Server header from the settings will mean that the CouchDB server header is replaced with the MochiWeb server header. .. config:option:: authentication_handlers :: Authentication handlers List of authentication handlers used by CouchDB. You may extend them via third-party plugins or remove some of them if you won't let users to use one of provided methods:: [chttpd] authentication_handlers = {chttpd_auth, cookie_authentication_handler}, {chttpd_auth, default_authentication_handler} - ``{chttpd_auth, cookie_authentication_handler}``: used for Cookie auth; - ``{chttpd_auth, proxy_authentication_handler}``: used for Proxy auth; - ``{chttpd_auth, jwt_authentication_handler}``: used for JWT auth; - ``{chttpd_auth, default_authentication_handler}``: used for Basic auth; - ``{couch_httpd_auth, null_authentication_handler}``: disables auth, breaks CouchDB. .. config:option:: buffer_response :: Buffered response .. versionchanged:: 3.1.1 Set this to ``true`` to delay the start of a response until the end has been calculated. This increases memory usage, but simplifies client error handling as it eliminates the possibility that a response may be deliberately terminated midway through, due to a timeout. This config value may be changed at runtime, without impacting any in-flight responses. Even if this is set to ``false`` (the default), buffered responses can be enabled on a per-request basis for any delayed JSON response call by adding ``?buffer_response=true`` to the request's parameters. .. config:option:: allow_jsonp :: Enables JSONP support .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section The ``true`` value of this option enables `JSONP`_ support (it's ``false`` by default):: [chttpd] allow_jsonp = false .. _JSONP: https://en.wikipedia.org/wiki/JSONP .. config:option:: changes_timeout :: Changes feed timeout .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section Specifies default `timeout` value for :ref:`Changes Feed ` in milliseconds (60000 by default):: [chttpd] changes_timeout = 60000 ; 60 seconds .. config:option:: config_whitelist :: Config options whitelist .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section Sets the configuration modification whitelist. Only whitelisted values may be changed via the :ref:`config API `. To allow the admin to change this value over HTTP, remember to include ``{chttpd,config_whitelist}`` itself. Excluding it from the list would require editing this file to update the whitelist:: [chttpd] config_whitelist = [{chttpd,config_whitelist}, {log,level}, {etc,etc}] .. config:option:: enable_cors :: Activates CORS .. versionadded:: 1.3 .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section Controls :ref:`CORS ` feature:: [chttpd] enable_cors = false .. config:option:: secure_rewrites :: Default request handler .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section This option allow to isolate databases via subdomains:: [chttpd] secure_rewrites = true .. config:option:: x_forwarded_host :: X-Forwarder-Host .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section The `x_forwarded_host` header (``X-Forwarded-Host`` by default) is used to forward the original value of the ``Host`` header field in case, for example, if a reverse proxy is rewriting the "Host" header field to some internal host name before forward the request to CouchDB:: [chttpd] x_forwarded_host = X-Forwarded-Host This header has higher priority above ``Host`` one, if only it exists in the request. .. config:option:: x_forwarded_proto :: X-Forwarder-Proto .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section `x_forwarded_proto` header (``X-Forwarder-Proto`` by default) is used for identifying the originating protocol of an HTTP request, since a reverse proxy may communicate with CouchDB instance using HTTP even if the request to the reverse proxy is HTTPS:: [chttpd] x_forwarded_proto = X-Forwarded-Proto .. config:option:: x_forwarded_ssl :: X-Forwarder-Ssl .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section The `x_forwarded_ssl` header (``X-Forwarded-Ssl`` by default) tells CouchDB that it should use the `https` scheme instead of the `http`. Actually, it's a synonym for ``X-Forwarded-Proto: https`` header, but used by some reverse proxies:: [chttpd] x_forwarded_ssl = X-Forwarded-Ssl .. config:option:: enable_xframe_options :: Controls X-Frame-Options header .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section Controls :ref:`Enables or disabled ` feature:: [chttpd] enable_xframe_options = false .. config:option:: max_http_request_size :: Maximum HTTP request body size .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section Limit the maximum size of the HTTP request body. This setting applies to all requests and it doesn't discriminate between single vs. multi-document operations. So setting it to 1MB would block a `PUT` of a document larger than 1MB, but it might also block a ``_bulk_docs`` update of 1000 1KB documents, or a multipart/related update of a small document followed by two 512KB attachments. This setting is intended to be used as a protection against maliciously large HTTP requests rather than for limiting maximum document sizes. :: [chttpd] max_http_request_size = 4294967296 ; 4 GB .. warning:: Before version 2.1.0 :config:option:`couchdb/max_document_size` was implemented effectively as ``max_http_request_size``. That is, it checked HTTP request bodies instead of document sizes. After the upgrade, it is advisable to review the usage of these configuration settings. .. config:option:: bulk_get_use_batches :: Use the optimized bulk_get implementation .. versionadded:: 3.3 Set to false to revert to a previous ``_bulk_get`` implementation using single doc fetches internally. Using batches should be faster, however there may be bugs in the new new implemention, so expose this option to allow reverting to the old behavior. :: [chttpd] bulk_get_use_batches = true .. config:option:: admin_only_all_dbs :: Require admin for ``_all_dbs`` and ``_dbs_info`` .. versionadded:: 2.2 implemented for ``_all_dbs`` defaulting to ``false`` .. versionchanged:: 3.0 default switched to ``true``, applies to ``_all_dbs`` .. versionchanged:: 3.3 applies for ``_all_dbs`` and ``_dbs_info`` When set to ``true`` admin is required to access ``_all_dbs`` and ``_dbs_info``. :: [chttpd] admin_only_all_dbs = true .. config:option:: server_header_versions :: Whether to send version info Server header .. versionadded:: 3.4 Set to false to remove the CouchDB and Erlang/OTP versions from the Server response header. :: [chttpd] server_header_versions = true .. config:option:: disconnect_check_msec :: Client disconnection check interval .. versionadded:: 3.4 How often, in milliseconds, to check for client disconnects while processing streaming requests such as _all_docs, _find, _changes and views. :: [chttpd] disconnect_check_msec = 30000 .. config:option:: disconnect_check_jitter_msec :: Client disconnection check jitter .. versionadded:: 3.4 How much random jitter to apply to the ``disconnect_check_msec`` period. This is to avoid stampede in case of a large number of concurrent clients. :: [chttpd] disconnect_check_jitter_msec = 15000 .. config:section:: httpd :: HTTP Server Options .. versionchanged:: 3.2 These options were moved to [chttpd] section: `allow_jsonp`, `changes_timeout`, `config_whitelist`, `enable_cors`, `secure_rewrites`, `x_forwarded_host`, `x_forwarded_proto`, `x_forwarded_ssl`, `enable_xframe_options`, `max_http_request_size`. .. config:option:: server_options :: MochiWeb Server Options Server options for the MochiWeb component of CouchDB can be added to the configuration files:: [httpd] server_options = [{backlog, 128}, {acceptor_pool_size, 16}] The options supported are a subset of full options supported by the TCP/IP stack. A list of the supported options are provided in the `Erlang inet`_ documentation. .. _Erlang inet: http://www.erlang.org/doc/man/inet.html#setopts-2 .. config:option:: socket_options :: Socket Options The socket options for the listening socket in CouchDB, as set at the beginning of ever request, can be specified as a list of tuples. For example:: [httpd] socket_options = [{sndbuf, 262144}] The options supported are a subset of full options supported by the TCP/IP stack. A list of the supported options are provided in the `Erlang inet`_ documentation. .. _Erlang inet: http://www.erlang.org/doc/man/inet.html#setopts-2 .. _config/ssl: HTTPS (SSL/TLS) Options ======================= .. config:section:: ssl :: HTTPS (SSL/TLS) Options CouchDB supports TLS/SSL natively, without the use of a proxy server. HTTPS setup can be tricky, but the configuration in CouchDB was designed to be as easy as possible. All you need is two files; a certificate and a private key. If you have an official certificate from a certificate authority, both should be in your possession already. If you just want to try this out and don't want to go through the hassle of obtaining an official certificate, you can create a self-signed certificate. Everything will work the same, but clients will get a warning about an insecure certificate. You will need the `OpenSSL`_ command line tool installed. It probably already is. .. code-block:: bash shell> mkdir /etc/couchdb/cert shell> cd /etc/couchdb/cert shell> openssl genrsa > privkey.pem shell> openssl req -new -x509 -key privkey.pem -out couchdb.pem -days 1095 shell> chmod 600 privkey.pem couchdb.pem shell> chown couchdb privkey.pem couchdb.pem Now, you need to edit CouchDB's configuration, by editing your ``local.ini`` file. Here is what you need to do. Under the ``[ssl]`` section, enable HTTPS and set up the newly generated certificates:: [ssl] enable = true cert_file = /etc/couchdb/cert/couchdb.pem key_file = /etc/couchdb/cert/privkey.pem For more information please read `certificates HOWTO`_. Now start (or restart) CouchDB. You should be able to connect to it using HTTPS on port 6984: .. code-block:: console shell> curl https://127.0.0.1:6984/ curl: (60) SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed More details here: http://curl.haxx.se/docs/sslcerts.html curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option. If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL). If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option. Oh no! What happened?! Remember, clients will notify their users that your certificate is self signed. ``curl`` is the client in this case and it notifies you. Luckily you trust yourself (don't you?) and you can specify the ``-k`` option as the message reads: .. code-block:: console shell> curl -k https://127.0.0.1:6984/ {"couchdb":"Welcome","version":"1.5.0"} All done. For performance reasons, and for ease of setup, you may still wish to terminate HTTPS connections at your load balancer / reverse proxy, then use unencrypted HTTP between it and your CouchDB cluster. This is a recommended approach. Additional detail may be available in the `CouchDB wiki`_. .. _`certificates HOWTO`: http://www.openssl.org/docs/HOWTO/certificates.txt .. _OpenSSL: http://www.openssl.org/ .. _`CouchDB wiki`: https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=48203146 .. config:option:: cacert_file :: CA Certificate file The path to a file containing PEM encoded CA certificates. The CA certificates are used to build the server certificate chain, and for client authentication. Also the CAs are used in the list of acceptable client CAs passed to the client when a certificate is requested. May be omitted if there is no need to verify the client and if there are not any intermediate CAs for the server certificate:: [ssl] cacert_file = /etc/ssl/certs/ca-certificates.crt .. config:option:: cert_file :: Certificate file Path to a file containing the user's certificate:: [ssl] cert_file = /etc/couchdb/cert/couchdb.pem .. config:option:: key_file :: Certificate key file Path to file containing user's private PEM encoded key:: [ssl] key_file = /etc/couchdb/cert/privkey.pem .. config:option:: password :: Certificate key password String containing the user's password. Only used if the private key file is password protected:: [ssl] password = somepassword .. config:option:: ssl_certificate_max_depth :: Maximum peer certificate depth Maximum peer certificate depth (must be set even if certificate validation is off):: [ssl] ssl_certificate_max_depth = 1 .. config:option:: verify_fun :: SSL verification function The verification fun (optional) if not specified, the default verification fun will be used:: [ssl] verify_fun = {Module, VerifyFun} .. config:option:: verify_ssl_certificates :: Enable certificate verification Set to ``true`` to validate peer certificates:: [ssl] verify_ssl_certificates = false .. config:option:: fail_if_no_peer_cert :: Require presence of client certificate if certificate verification is enabled Set to ``true`` to terminate the TLS/SSL handshake with a ``handshake_failure`` alert message if the client does not send a certificate. Only used if ``verify_ssl_certificates`` is ``true``. If set to ``false`` it will only fail if the client sends an invalid certificate (an empty certificate is considered valid):: [ssl] fail_if_no_peer_cert = false .. config:option:: secure_renegotiate :: Enable secure renegotiation Set to ``true`` to reject renegotiation attempt that does not live up to RFC 5746:: [ssl] secure_renegotiate = true .. config:option:: ciphers :: Specify permitted server cipher list Set to the cipher suites that should be supported which can be specified in erlang format "{ecdhe_ecdsa,aes_128_cbc,sha256}" or in OpenSSL format "ECDHE-ECDSA-AES128-SHA256". :: [ssl] ciphers = ["ECDHE-ECDSA-AES128-SHA256", "ECDHE-ECDSA-AES128-SHA"] .. config:option:: tls_versions :: Specify permitted server SSL/TLS protocol versions Set to a list of permitted SSL/TLS protocol versions:: [ssl] tls_versions = [tlsv1 | 'tlsv1.1' | 'tlsv1.2'] .. _cors: .. _config/cors: Cross-Origin Resource Sharing ============================= .. config:section:: cors :: Cross-Origin Resource Sharing .. versionadded:: 1.3 added CORS support, see JIRA :issue:`431` .. versionchanged:: 3.2 moved from [httpd] to [chttpd] section `CORS`, or "Cross-Origin Resource Sharing", allows a resource such as a web page running JavaScript inside a browser, to make AJAX requests (XMLHttpRequests) to a different domain, without compromising the security of either party. A typical use case is to have a static website hosted on a CDN make requests to another resource, such as a hosted CouchDB instance. This avoids needing an intermediary proxy, using `JSONP` or similar workarounds to retrieve and host content. While CouchDB's integrated HTTP server has support for document attachments makes this less of a constraint for pure CouchDB projects, there are many cases where separating the static content from the database access is desirable, and CORS makes this very straightforward. By supporting CORS functionality, a CouchDB instance can accept direct connections to protected databases and instances, without the browser functionality being blocked due to same-origin constraints. CORS is supported today on over 90% of recent browsers. CORS support is provided as experimental functionality in 1.3, and as such will need to be enabled specifically in CouchDB's configuration. While all origins are forbidden from making requests by default, support is available for simple requests, preflight requests and per-vhost configuration. This section requires :option:`chttpd/enable_cors` option have ``true`` value:: [chttpd] enable_cors = true .. config:option:: credentials :: Enable credentials support in CouchDB By default, neither authentication headers nor cookies are included in requests and responses. To do so requires both setting ``XmlHttpRequest.withCredentials = true`` on the request object in the browser and enabling credentials support in CouchDB. :: [cors] credentials = true CouchDB will respond to a credentials-enabled CORS request with an additional header, ``Access-Control-Allow-Credentials=true``. .. config:option:: origins :: List of allowed origins List of origins separated by a comma, ``*`` means accept all. You can’t set ``origins = *`` and ``credentials = true`` option at the same time:: [cors] origins = * Access can be restricted by protocol, host and optionally by port. Origins must follow the scheme: http://example.com:80:: [cors] origins = http://localhost, https://localhost, http://couch.mydev.name:8080 Note that by default, no origins are accepted. You must define them explicitly. .. config:option:: headers :: List of accepted headers List of accepted headers separated by a comma:: [cors] headers = X-Couch-Id, X-Couch-Rev .. config:option:: methods :: List of accepted methods List of accepted methods:: [cors] methods = GET,POST .. config:option:: max_age :: Set Access-Control-Max-Age header Sets the ``Access-Control-Max-Age`` header in seconds. Use it to avoid repeated ``OPTIONS`` requests. [cors] max_age = 3600 .. seealso:: Original JIRA `implementation ticket `_ Standards and References: - IETF RFCs relating to methods: :rfc:`2618`, :rfc:`2817`, :rfc:`5789` - IETF RFC for Web Origins: :rfc:`6454` - W3C `CORS standard `_ Mozilla Developer Network Resources: - `Same origin policy for URIs `_ - `HTTP Access Control `_ - `Server-side Access Control `_ - `JavaScript same origin policy `_ Client-side CORS support and usage: - `CORS browser support matrix `_ - `COS tutorial `_ - `XHR with CORS `_ Per Virtual Host Configuration ------------------------------ .. warning:: Virtual Hosts are deprecated in CouchDB 3.0, and will be removed in CouchDB 4.0. To set the options for a :section:`vhosts`, you will need to create a section with the vhost name prefixed by ``cors:``. Example case for the vhost `example.com`:: [cors:example.com] credentials = false ; List of origins separated by a comma origins = * ; List of accepted headers separated by a comma headers = X-CouchDB-Header ; List of accepted methods methods = HEAD, GET A video from 2010 on vhost and rewrite configuration `is available `_, but is not guaranteed to match current syntax or behaviour. .. _config/vhosts: Virtual Hosts ============= .. warning:: Virtual Hosts are deprecated in CouchDB 3.0, and will be removed in CouchDB 4.0. .. config:section:: vhosts :: Virtual Hosts CouchDB can map requests to different locations based on the ``Host`` header, even if they arrive on the same inbound IP address. This allows different virtual hosts on the same machine to map to different databases or design documents, etc. The most common use case is to map a virtual host to a :ref:`Rewrite Handler `, to provide full control over the application's URIs. To add a virtual host, add a `CNAME` pointer to the DNS for your domain name. For development and testing, it is sufficient to add an entry in the hosts file, typically `/etc/hosts`` on Unix-like operating systems: .. code-block:: text # CouchDB vhost definitions, refer to local.ini for further details 127.0.0.1 couchdb.local Test that this is working: .. code-block:: bash $ ping -n 2 couchdb.local PING couchdb.local (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost (127.0.0.1): icmp_req=1 ttl=64 time=0.025 ms 64 bytes from localhost (127.0.0.1): icmp_req=2 ttl=64 time=0.051 ms Finally, add an entry to your :ref:`configuration file ` in the ``[vhosts]`` section:: [vhosts] couchdb.local:5984 = /example *.couchdb.local:5984 = /example If your CouchDB is listening on the default HTTP port (80), or is sitting behind a proxy, then you don't need to specify a port number in the ``vhost`` key. The first line will rewrite the request to display the content of the `example` database. This rule works only if the ``Host`` header is ``couchdb.local`` and won't work for `CNAMEs`. The second rule, on the other hand, matches all `CNAMEs` to `example` db, so that both `www.couchdb.local` and `db.couchdb.local` will work. Rewriting Hosts to a Path ------------------------- Like in the :ref:`_rewrite ` handler you can match some variable and use them to create the target path. Some examples:: [vhosts] *.couchdb.local = /* :dbname. = /:dbname :ddocname.:dbname.example.com = /:dbname/_design/:ddocname/_rewrite The first rule passes the wildcard as ``dbname``. The second one does the same, but uses a variable name. And the third one allows you to use any URL with ``ddocname`` in any database with ``dbname``. .. _xframe_options: .. _config/xframe_options: X-Frame-Options ============================= X-Frame-Options is a response header that controls whether a http response can be embedded in a ,