NeoFS is a decentralized distributed object storage integrated with the NEO Blockchain.

---

NeoFS HTTP Protocol Gateway

NeoFS HTTP Protocol Gateway bridges NeoFS internal protocol and HTTP standard.

• you can download one file per request from NeoFS Network
• you can upload one file per request into the NeoFS Network

Installation

go get -u github.com/nspcc-dev/neofs-http-gate

Or you can call make to build it from the cloned repository (the binary will end up in bin/neofs-http-gw).

Notable make targets:

dep          Check and ensure dependencies
image        Build clean docker image
dirty-image  Build dirty docker image with host-built binaries
fmts         Run all code formatters
lint         Run linters
version      Show current version

Or you can also use a Docker image provided for released (and occasionaly unreleased) versions of gateway (:latest points to the latest stable release).

Execution

HTTP gateway itself is not a NeoFS node, so to access NeoFS it uses node's gRPC interface and you need to provide some node that it will connect to. This can be done either via -p parameter or via HTTP_GW_PEERS_<N>_ADDRESS and HTTP_GW_PEERS_<N>_WEIGHT environment variables (the gate supports multiple NeoFS nodes with weighted load balancing).

These two commands are functionally equivalent, they run the gate with one backend node (and otherwise default settings):

$ neofs-http-gw -p 192.168.130.72:8080
$ HTTP_GW_PEERS_0_ADDRESS=192.168.130.72:8080 neofs-http-gw

Configuration

In general, everything available as CLI parameter can also be specified via environment variables, so they're not specifically mentioned in most cases (see --help also).

Nodes and weights

You can specify multiple -p options to add more NeoFS nodes, this will make gateway spread requests equally among them (using weight 1 for every node):

$ neofs-http-gw -p 192.168.130.72:8080 -p 192.168.130.71:8080

If you want some specific load distribution proportions, use weights, but they can only be specified via environment variables:

$ HTTP_GW_PEERS_0_ADDRESS=192.168.130.72:8080 HTTP_GW_PEERS_0_WEIGHT=9 \
  HTTP_GW_PEERS_1_ADDRESS=192.168.130.71:8080 HTTP_GW_PEERS_1_WEIGHT=1 neofs-http-gw

This command will make gateway use 192.168.130.72 for 90% of requests and 192.168.130.71 for remaining 10%.

Keys

By default gateway autogenerates key pair it will use for NeoFS requests. If for some reason you need to have static keys you can pass them via --key parameter. The key can be a path to private key file (as raw bytes), a hex string or (unencrypted) WIF string. Example:

$ neofs-http-gw -p 192.168.130.72:8080 -k KxDgvEKzgSBPPfuVfw67oPQBSjidEiqTHURKSDL1R7yGaGYAeYnr

Binding and TLS

Gateway binds to 0.0.0.0:8082 by default and you can change that with --listen_address option.

It can also provide TLS interface for its users, just specify paths to key and certificate files via --tls_key and --tls_certificate parameters. Note that using these options makes gateway TLS-only, if you need to serve both TLS and plain text HTTP you either have to run two gateway instances or use some external redirecting solution.

Example to bind to 192.168.130.130:443 and serve TLS there:

$ neofs-http-gw -p 192.168.130.72:8080 --listen_address 192.168.130.130:443 \
  --tls_key=key.pem --tls_certificate=cert.pem

HTTP parameters

You can tune HTTP read and write buffer sizes as well as timeouts with HTTP_GW_WEB_READ_BUFFER_SIZE, HTTP_GW_WEB_READ_TIMEOUT, HTTP_GW_WEB_WRITE_BUFFER_SIZE and HTTP_GW_WEB_WRITE_TIMEOUT environment variables.

HTTP_GW_WEB_STREAM_REQUEST_BODY environment variable can be used to disable request body streaming (effectively it'll make gateway accept file completely first and only then try sending it to NeoFS).

HTTP_GW_WEB_MAX_REQUEST_BODY_SIZE controls maximum request body size limiting uploads to files slightly lower than this limit.

NeoFS parameters

Gateway can automatically set timestamps for uploaded files based on local time source, use HTTP_GW_UPLOAD_HEADER_USE_DEFAULT_TIMESTAMP environment variable to control this behavior.

Monitoring and metrics

Pprof and Prometheus are integrated into the gateway, but not enabled by default. To enable them use --pprof and --metrics flags or HTTP_GW_PPROF/HTTP_GW_METRICS environment variables.

Timeouts

You can tune gRPC interface parameters with --connect_timeout (for connection to node) and --request_timeout (for request processing over established connection) options as well as HTTP_GW_KEEPALIVE_TIME (peer pinging interval), HTTP_GW_KEEPALIVE_TIMEOUT (peer pinging timeout) and HTTP_GW_KEEPALIVE_PERMIT_WITHOUT_STREAM environment variables.

gRPC-level checks allow gateway to detect dead peers, but it declares them unhealthy at pool level once per --rebalance_timer interval, so check for it if needed.

All timing options accept values with suffixes, so "15s" is 15 seconds and "2m" is 2 minutes.

Logging

--verbose flag enables gRPC logging and there is a number of environment variables to tune logging behavior:

HTTP_GW_LOGGER_FORMAT=string                     - Logger format
HTTP_GW_LOGGER_LEVEL=string                      - Logger level
HTTP_GW_LOGGER_NO_CALLER=bool                    - Logger don't show caller
HTTP_GW_LOGGER_NO_DISCLAIMER=bool                - Logger don't show application name/version
HTTP_GW_LOGGER_SAMPLING_INITIAL=int              - Logger sampling initial
HTTP_GW_LOGGER_SAMPLING_THEREAFTER=int           - Logger sampling thereafter
HTTP_GW_LOGGER_TRACE_LEVEL=string                - Logger show trace on level

HTTP API provided

This gateway intentionally provides limited feature set and doesn't try to substitute (or completely wrap) regular gRPC NeoFS interface. You can download and upload objects with it, but deleting, searching, managing ACLs, creating containers and other activities are not supported and not planned to be supported.

Downloading

Requests

Basic downloading involves container and object ID and is done via GET requests to /get/$CID/$OID path, like this:

$ wget http://localhost:8082/get/Dxhf4PNprrJHWWTG5RGLdfLkJiSQ3AQqit1MSnEPRkDZ/2m8PtaoricLouCn5zE8hAFr3gZEBDCZFe9BEgVJTSocY

There is also more complex interface provided for attribute-based downloads, it's usually used to retrieve files by their names, but any other attribute can be used as well. The generic syntax for it looks like this:

/get_by_attribute/$CID/$ATTRIBUTE_NAME/$ATTRIBUTE_VALUE

where $CID is a container ID, $ATTRIBUTE_NAME is the name of the attribute we want to use and ATTRIBUTE_VALUE is the value of this attribute that the target object should have.

If multiple objects have specified attribute with specified value, then the first one of them is returned (and you can't get others via this interface).

Example for file name attribute:

$ wget http://localhost:8082/get_by_attribute/88GdaZFTcYJn1dqiSECss8kKPmmun6d6BfvC4zhwfLYM/FileName/cat.jpeg

Some other user-defined attribute:

$ wget http://localhost:8082/get_by_attribute/Dxhf4PNprrJHWWTG5RGLdfLkJiSQ3AQqit1MSnEPRkDZ/Ololo/100500

An optional download=true argument for Content-Disposition management is also supported (more on that below):

$ wget http://localhost:8082/get/Dxhf4PNprrJHWWTG5RGLdfLkJiSQ3AQqit1MSnEPRkDZ/2m8PtaoricLouCn5zE8hAFr3gZEBDCZFe9BEgVJTSocY?download=true

Replies

You get object contents in the reply body, but at the same time you also get a set of reply headers generated using the following rules:

• Content-Length is set to the length of the object
• Content-Type is autodetected dynamically by gateway
• Content-Disposition is inline for regular requests and attachment for requests with download=true argument, filename is also added if there is FileName attribute set for this object
• Last-Modified header is set to Timestamp attribute value if it's present for the object
• x-container-id contains container ID
• x-object-id contains object ID
• x-owner-id contains owner address
• all the other NeoFS attributes are converted to X-Attribute-* headers (but only if they can be safely represented in HTTP header), for example FileName attribute becomes X-Attribute-FileName header

Uploading

You can POST files to /upload/$CID path where $CID is container ID. The request must contain multipart form with mandatory filename parameter. Only one part in multipart form will be processed, so to upload another file just issue new POST request.

Example request:

$ curl -F 'file=@cat.jpeg;filename=cat.jpeg' http://localhost:8082/upload/Dxhf4PNprrJHWWTG5RGLdfLkJiSQ3AQqit1MSnEPRkDZ

Chunked encoding is supported by the server (but check for request read timeouts if you're planning some streaming). You can try streaming support with large file piped through named FIFO pipe:

$ mkfifo pipe
$ cat video.mp4 > pipe &
$ curl --no-buffer -F 'file=@pipe;filename=catvideo.mp4' http://localhost:8082/upload/Dxhf4PNprrJHWWTG5RGLdfLkJiSQ3AQqit1MSnEPRkDZ

You can also add some attributes to your file using the following rules:

• all "X-Attribute-*" headers get converted to object attributes with "X-Attribute-" prefix stripped, that is if you add "X-Attribute-Ololo: 100500" header to your request the resulting object will get "Ololo: 100500" attribute
• "X-Attribute-NEOFS-*" headers are special, they're used to set internal NeoFS attributes starting with __NEOFS__ prefix, for these attributes all dashes get converted to underscores and all letters are capitalized. For example, you can use "X-Attribute-NEOFS-Expiration-Epoch" header to set __NEOFS__EXPIRATION_EPOCH attribute
• FileName attribute is set from multipart's filename if not set explicitly via X-Attribute-FileName header
• Timestamp attribute can be set using gateway local time if using HTTP_GW_UPLOAD_HEADER_USE_DEFAULT_TIMESTAMP option and if request doesn't provide X-Attribute-Timestamp header of its own

For successful uploads you get JSON data in reply body with container and object ID, like this:

{
        "object_id": "9ANhbry2ryjJY1NZbcjryJMRXG5uGNKd73kD3V1sVFsX",
        "container_id": "Dxhf4PNprrJHWWTG5RGLdfLkJiSQ3AQqit1MSnEPRkDZ"
}

Authentication

You can always upload files to public containers (open for anyone to put objects into), but for restricted containers you need to explicitly allow PUT operations for request signed with your HTTP Protocol Gateway keys.

If your don't want to manage gateway's secret keys and adjust eACL rules when gateway configuration changes (new gate, key rotation, etc) or you plan to use public services, there is an option to let your application backend (or you) to issue Bearer Tokens ans pass them from the client via gate down to NeoFS level to grant access.

NeoFS Bearer Token basically is a container owner-signed ACL data (refer to NeoFS documentation for more details). There are two options to pass them to gateway:

• "Authorization" header with "Bearer" type and base64-encoded token in credentials field
• "__context_bearer_token_key" cookie with base64-encoded token contents

For example you have a mobile application frontend with a backend part storing data in NeoFS. When user authorizes in mobile app, the backend issues a NeoFS Bearer token and provides it to the frontend. Then the mobile app may generate some data and upload it via any available NeoFS HTTP Protocol Gateway by adding the corresponding header to the upload request. Accessing the ACL protected data works the same way.

Metrics and Pprof

If enabled, Prometheus metrics are available at /metrics/ path and Pprof at /debug/pprof.