Append data to the url query

https://daniel.haxx.se/blog/2022/11/10/append-data-to-the-url-query/

by soheilpro • 4 years ago

87 32 4 years ago

daniel.haxx.se

jrochkind12• 4 years ago

This is curl’s 249th command line option

ainar-g• 4 years ago

Almost quarter of a thousand. Yay!

That does raise an interesting question though. If one wanted to create a command-line tool (or, rather, toolset) as comprehensive as curl, but with a much smaller API surface, how would they go about it? Sure, some of these flags are just shorthands, and some of them could be removed entirely (-o → stdout redirection), but that still leaves a lot of options.

pjc50• 4 years ago

How would you keep it there? You'd have to spend a lot of effort discouraging feature requests.

tyingq• 4 years ago

Curl supports a lot of crazy stuff that adds command line options, like IMAP/LDAP/POP3/SMTP means adding --login-options, --mail-auth, --mail-from, --mail-rcpt-allowfails, --mail-rcpt. If you read the man page, you'll find other flags that aren't really central to a http(s) fetch tool, like ftp, tftp.

mmh0000• 4 years ago

Ah. But -o is useful.

What if I’m running curl directly without a shell (e.g. in a container). How else would I save the output to a file?

jrochkind12• 4 years ago

Curl is really really big on backwards compatibility, which I don't mean to critisize.

If you were starting over from scratch even trying to make it curl-like, you could probably trim down the options substantially.

The OP is in fact an example of a new option that can more-or-less cover the same functionality as some old options, plus more, but the old options remain.

UI_at_80x24• 4 years ago

Wow. Every time I've tried to dig into the man pages to find an option that I need it's been overwhelming; and now I know why!

This is one seriously under appreciated piece of code, and I am so grateful that it exists.

bpoyner• 4 years ago

They changed the curl man page in the last year so that all options have 'see also' recommendations. The documentation is amazing.

https://twitter.com/bagder/status/1460867775690387457

pablobaz• 4 years ago

I wonder will they have a party when they hit 250?

danuker2• 4 years ago

I would do it at 256

nickcw• 4 years ago

This made me smile!

And also

    $ rclone help flags . | grep "^ *--"  | wc -l
    665

(yes rclone has a command to grep its flags `rclone help flags <regex>`!)

ape4• 4 years ago

The article says the new option replaces the -G option. But, of course, for compatibility they cannot remove -G.

pmoriarty• 4 years ago

Daniel Stenberg, curl's lead developer, made a good tutorial video[1] on curl, focusing on advanced use of its HTTP options.

Here are some org-format notes I took on curl, mostly from the contents of that video: [2]

[1] https://www.youtube.com/watch?v=I6id1Y0YuNk

[2] https://paste.grml.org/plain/3559

silverwind• 4 years ago

curl inferring the HTTP method from options is just bad design. It should have always been explicit via `-X`, but weirdly enough it sometimes warns when using that option.

Also, it seems some curl behaviours live in the past where only GET and POST verbs exists, ignoring others like PUT and PATCH.

chrsig2• 4 years ago

They didn't live in the past when implemented :)

Backwards compatibility is a wonderful thing, but leads to anachronisms 20 years later.

`-X` exists for anyone that doesn't want curl's divination

kh1• 4 years ago

When I use curl, it's mostly when I need to check header or to trace requests in the network, for which I just use -vvv. Simple one-off stuff.

So I wonder how much demand there actually is for advanced features like this. When I need to make POST requests with queries and data, I would just use python because I most likely need to process the response (parse html, store json output to database, etc.).

Adding advanced features are nice, but IMO this might lead to over-engineering and it might be hard to maintain down the line.

chrsig2• 4 years ago

Adding advanced features are nice, but IMO this might lead to over-engineering and it might be hard to maintain down the line.

curl's not exactly a new project -- this is 'down the line' for it.

I personally welcome the change. I wont use it often, but when I will, I'll be quite happy that it's there. There are a number of other features I'd give up in it's stead.

bfung• 4 years ago

More than several times, there are data APIs that return raw text/csv, esp taking data from older systems.

Writing a scraper for those, bash & curl comes in handy w/o needing extra cruft of file writing ceremonies (ex: with open…), just pipe straight to file.

selcuka• 4 years ago

Adding advanced features are nice, but IMO this might lead to over-engineering and it might be hard to maintain down the line.

Well, one person [1] has been maintaining it since 1998. It's a good thing that HTTP doesn't change that often.

[1] https://daniel.haxx.se/

csours2• 4 years ago

I thought this was going to be about base64 encoded json query param(s) - instead of posting base64 or making a bunch of different params, do a GET with one param of base64 encoded json. Easy for the client, easy for the server, easy to share, only downside that I see is that it makes things a bit obtuse for users, but an extension or browser affordance could fix that.

rpastuszak• 4 years ago

If you're into this stuff, you might enjoy my "Twitter as a CDN tool", here's pong in a single Tweet: https://twitter.com/rafalpast/status/1316836397903474688

Easy for the client, easy for the server, easy to share, only downside that I see is that it makes things a bit obtuse for users

There are more downsides:

- processing and creating payload can be harder are you're passing plaintext w. ca. 30% size increase on average

- base64-encoded assets (e.g. SVGs) would cause a huge performance drop in WebKit (this probably has improved since the last time I ran benchmarks).

- since you're encoding content and not its location, you can't easily update the underlying resource (hence to update my version of Pong, I'd need to create a new unique URL). IIRC IPFS suffers (used to?) from a similar issue

- not an issue now, but still was 1-2 years ago: some browsers would allow only for 2 or 4kb of text in URL

csours2• 4 years ago

Hah, that Twitter thing is neat.

not an issue now, but still was 1-2 years ago: some browsers would allow only for 2 or 4kb of text in URL

Yes, I had in mind smaller payloads, things that would have been query params on a GET

r_c_a_d• 4 years ago

Yes, I think this is how Wordle did the migration to NY Times without losing game history. The original site did a redirect to nytimes.com/something/wordle?data=X where X was the game history. Quite clever, I thought.

cagmz• 4 years ago

Does this technique have a name?

cdelsolar• 4 years ago

curl is amazing. I thought I'd read somewhere that it's on Mars.

sadjad• 4 years ago

Yup! He has a badge for it on Github: https://github.com/bagder?tab=achievements

daveevad• 4 years ago

All the other github hosted software which is eligible for this achievement is available https://docs.github.com/en/account-and-profile/setting-up-an...

edit: oh no, log4j-2.11.0

blahgeek• 4 years ago

Curl is great because it’s stable and universally available.

But for interactive CLI usage, I always find its command line options non intuitive - take this for example, I don’t think I can really remember the difference between -d and —data-url and —url-query if I don’t use it daily. I think that the price to pay to make it backward compatible.

For that reason, I would recommend httpie as a replacement, which provides a more intuitive interface.

Append data to the url query

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