### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 22, 2025, 4:21pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/1 "2025-04-22T16:21:50Z")
http/server… How to get the request body?
The POST body from the client is JSON in the format below:
```auto
{
"service": "serviceName",
"method": "methodName",
"params": {}
}
```
Server side I tried to retrieve that like this:
```auto
postbody = context.request.body.to_s
```
but that gives me something like: `#`
How do I get that request body as a string?
---
### Author:  [@straight-shoota](https://forum.crystal-lang.org/u/straight-shoota)
#### Post date: [April 22, 2025, 4:42pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/2 "2025-04-22T16:42:12Z")
`HTTP::FixedLengthContent` is an [`IO`](https://crystal-lang.org/api/1.16.1/IO.html) stream. You can consume it partially (bytewise), or entirely with [`#gets_to_end`](https://crystal-lang.org/api/1.16.1/IO.html#gets_to_end%3AString-instance-method):
```cr
postbody = context.request.body.gets_to_end
```
---
### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 22, 2025, 5:09pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/3 "2025-04-22T17:09:33Z")
> [@straight-shoota](#):
>
> `context.request.body.gets_to_end`
I can’t even run with that, I get the following error:
`Error: undefined method 'gets_to_end' for Nil (compile-time type is (IO | Nil))`
---
### Author:  [@Blacksmoke16](https://forum.crystal-lang.org/u/Blacksmoke16)
#### Post date: [April 22, 2025, 5:30pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/4 "2025-04-22T17:30:13Z")
It’s possible a request does not have a body, so it could be `nil`. If you are 100% sure there will be one, could do something like `context.request.body.not_nil!.gets_to_end`. Otherwise might be better to check for one and return a proper HTTP error back.
---
### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 22, 2025, 5:51pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/5 "2025-04-22T17:51:12Z")
> [@Blacksmoke16](#):
>
> context.request.body.not\_nil!.gets\_to\_end
Thank you.
If the body is missing can I be sure this will just resolve to an empty string?
---
### Author:  [@Blacksmoke16](https://forum.crystal-lang.org/u/Blacksmoke16)
#### Post date: [April 22, 2025, 5:59pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/6 "2025-04-22T17:59:11Z")
No, if the body is missing and you’re using `.not_nil!` it would likely result in an exception which would likely return a `500` error to the user. If this code is going to be used for real, I’d consider explicitly handling it by returning a `400` or something if there is no body and you’re expecting one.
---
### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 22, 2025, 6:30pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/7 "2025-04-22T18:30:02Z")
Sorry, I’m new to Crystal. I love the syntax and I seemed to be doing OK until I hit this bump in the road 😕
How can I test for nil in my code when the compiler won’t even let me run when that possibility exists?
`Error: undefined method 'gets_to_end' for Nil (compile-time type is (IO | Nil))`
---
### Author:  [@Blacksmoke16](https://forum.crystal-lang.org/u/Blacksmoke16)
#### Post date: [April 22, 2025, 6:42pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/8 "2025-04-22T18:42:16Z")
Something like this should do it, assuming you’re using the default HTTP server and not a framework:
```crystal
unless body = context.request.body
break context.response.respond_with_status(400, "Request is missing a body")
end
puts body.gets_to_end
```
---
### Author:  [@straight-shoota](https://forum.crystal-lang.org/u/straight-shoota)
#### Post date: [April 22, 2025, 8:52pm UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/9 "2025-04-22T20:52:35Z")
Alternative:
```cr
context.request.body.try(&.gets_to_end)
```
This evaluates to either a string containing the body content, or `nil` if there’s no body.
---
### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 23, 2025, 8:10am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/10 "2025-04-23T08:10:36Z")
Thank you both for your help.
This had me going for a while but I’ve found even if there is no body in the POST request `context.request.body` is still not nil…
```crystal
unless body = context.request.body
puts "It's nil"
return
end
puts typeof(body) # IO
postbody = body.gets_to_end
puts typeof(postbody) # String
if postbody == ""
puts "It's an empty string!" # is displayed
end
```
---
### Author:  [@straight-shoota](https://forum.crystal-lang.org/u/straight-shoota)
#### Post date: [April 23, 2025, 8:44am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/11 "2025-04-23T08:44:50Z")
What does the `POST` request look like?
---
### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 23, 2025, 9:10am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/12 "2025-04-23T09:10:39Z")
I just commented out the body:
```js
const response = await fetch("/", {
method: "POST",
//body: JSON.stringify({"service": "foo", "method": "bar", "params": ["baz"]})
});
console.log(response);
```
And now I currently have this in the server’s handler:
```crystal
begin
js = JSON.parse(context.request.body.not_nil!.gets_to_end)
rescue
do_error(context, HTTP::Status::BAD_REQUEST, "Malformed request", "text/plain")
return
end
```
---
### Author:  [@ysbaddaden](https://forum.crystal-lang.org/u/ysbaddaden)
#### Post date: [April 23, 2025, 9:59am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/13 "2025-04-23T09:59:56Z")
It’s possible the body ain’t nil but empty? Like the server is returning content-length zero or a chunked response with an empty body?
BTW: the nilable body sounds a bit harsh. Couldn’t it always return an empty IO object?
---
### Author:  [@straight-shoota](https://forum.crystal-lang.org/u/straight-shoota)
#### Post date: [April 23, 2025, 10:34am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/14 "2025-04-23T10:34:42Z")
That JS request sends the header `Content-Length: 0`. That implies an empty body (not a nil body), just as you observed.
> [@ysbaddaden](#):
>
> BTW: the nilable body sounds a bit harsh. Couldn’t it always return an empty IO object?
I was thinking the same.
It’s quite rare that the body is actually nil.
---
### Author:  [@luislavena](https://forum.crystal-lang.org/u/luislavena)
#### Post date: [April 23, 2025, 10:36am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/15 "2025-04-23T10:36:43Z")
> [@ysbaddaden](#):
>
> BTW: the nilable body sounds a bit harsh. Couldn’t it always return an empty IO object?
Oh, yes, please!
I had so many fights with code readability due that little detail.
Ended always with this noop pattern:
>
>
😿
---
### Author:  [@Steve](https://forum.crystal-lang.org/u/Steve)
#### Post date: [April 23, 2025, 11:25am UTC](https://forum.crystal-lang.org/t/http-server-how-to-get-the-request-body/7985/16 "2025-04-23T11:25:19Z")
> [@luislavena](#):
>
> ```crystal
> def parse_json(io : IO, type)
> type.from_json(io)
> end
>
> # no-op
> def parse_json(io : Nil, type)
> end
>
> ```
Quite a neat bit of lateral thinking there imo 😁