CURL 7.81 released: tool to transfer data from or to a server
curl is a tool to transfer data from or to a server, using one of the supported protocols (HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP or FILE). The command is designed to work without user interaction.
curl offers proxy support, user authentication, FTP uploading, HTTP posting, SSL connections, cookies, file transfer resume, Metalink, and many other features.
CURL 7.81 released.
Changelog
Changes:
Bugfixes:
- asyn-ares: ares_getaddrinfo needs no happy eyeballs timer
- azure: make the “w/o HTTP/SMTP/IMAP” build disable SSL proper
- BINDINGS: add cURL client for PostgreSQL
- BINDINGS: add one from Everything curl and update a link
- checksrc: detect more kinds of NULL comparisons we avoid
- CI: build examples for additional code verification
- CI: bump job to use mbedtls 3.1.0
- cmake: don’t set _USRDLL on a static Windows build
- cmake: prevent dev warning due to mismatched arg
- cmake: private identifiers use CURL_ instead of CMAKE_ prefix
- config.d: update documentation to match the path search
- configure: add -lm to configure for rustls build.
- configure: better diagnostics if hyper is built wrong
- configure: don’t enable TLS when –without-* flags are used
- configure: fix runtime-lib detection on macOS
- curl.1: require “see also” for every documented option
- curl: improve error message for –head with -J
- curl_easy_cleanup.3: remove from multi handle first
- curl_easy_escape.3: call curl_easy_cleanup in example
- curl_easy_unescape.3: call curl_easy_cleanup in example
- curl_multi_init.3: fix EXAMPLE formatting
- curl_multi_perform/socket_action.3: clarify what errors mean
- curl_share_setopt.3: split out options into their own manpages
- CURLOPT_STDERR.3: does not work with libcurl as a win32 DLL
- digest: compute user:realm:pass digest w/o userhash
- docs/checksrc: Add documentation for STRERROR
- docs/cmdline-opts: do not say “protocols: all”
- More…
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How to use curl
Basic GET
GET a single resource via its URI
The default operation is a GET:
curl http://api.example.com:8080/statuses/1234
GET multiple resources where IDs are in a range
Use square brackets with a dashed range:
curl http://api.example.com:8080/items/[1230-1234]
GET multiple resources where IDs aren’t in a range
Use curly braces with comma-delimited strings:
curl http://api.example.com:8080/products/{abc,def,ghi}/status
Using HTTP Headers
Accept only the application/json content-type
Use the header option: -H or –header
curl -H 'Accept: application/json' http://api.example.com:8080/items/1234
Add multiple headers
Use multiple -H options:
curl -H ‘Accept: application/json’ -H ‘Accept-Encoding: gzip’ http://api.example.com:8080/products/a1b2c3ef/status
Note: the output from this is likely to be unreadable because it’s gzipped!
More likely you’d use this with ETags:
curl -H ‘Accept: application/json’ -H ‘If-None-Match: “1cc044-172-3d9aee80″‘ http://api.example.com:8080/products/a1b2c3ef/status
Show the network and HTTP “conversation”
Use the verbose option: -v or –verbose
curl -v -H http://api.example.com
POST and PUT
POST data to a URI
To send data to the server, you use either POST or PUT, depending on what the API requires. To do a POST, you simply use the -d (–data) with some content:
curl -d "name=Ted" http://api.example.com:8080/customers
Note that this uses application/x-www-form-urlencoded as the Content-Type, i.e.,as if it was submitted by an HTML Form. You can use multiple -d options, which will be combined, e.g., these two commands produce the same content:
curl -d “first=Ted” -d “last=Young” http://api.example.com:8080/customers
curl -d “first=Ted&last=Young” http://api.example.com:8080/customers
If you want to send JSON, you’ll need to specify the Content-Type explicitly using the -H (header) option:
curl -d '{"name": "Ted"}' -H 'Content-Type: application/json' http://api.example.com:8080/items
PUT data to a URI
If you need to use the PUT method, you’ll need to override the method with the -X (–request) option:
curl -X PUT -d ‘{“name”: “Ted”}’ -H ‘Content-Type: application/json’ http://api.example.com:8080/items/1234
