feat: use get request by default, post if payload (#15862)

Hello, this PR resolves the second request of the issue
https://github.com/nushell/nushell/issues/10957, which involves using a
default verb based on the request. If a URL is provided, the command
will default to GET, and if data is provided, it will default to POST.
This means that the following pairs of commands are equivalent:

```
http --content-type application/json http://localhost:8000 {a:1}
http post --content-type application/json http://localhost:8000 {a:1}
```
```
http http://localhost:8000 "username"
http post http://localhost:8000 "username"
```
```
http http://localhost:8000
http get http://localhost:8000
```

The `http` command now accepts all flags of the `post` and `get`
commands. It will still display the help message if no subcommand is
provided, and the description has been updated accordingly. The logic in
the `http` command is minimal to delegate error management
responsibilities to the specific `run_get` and `run_post` functions.

crates/nu-command/src/network/http/get.rs

@@ -141,7 +141,7 @@ struct Arguments {
     redirect: Option<Spanned<String>>,
 }
 
-fn run_get(
+pub fn run_get(
     engine_state: &EngineState,
     stack: &mut Stack,
     call: &Call,

crates/nu-command/src/network/http/http_.rs

@@ -1,5 +1,8 @@
 use nu_engine::{command_prelude::*, get_full_help};
 
+use super::get::run_get;
+use super::post::run_post;
+
 #[derive(Clone)]
 pub struct Http;
 
@@ -10,7 +13,76 @@ impl Command for Http {
 
     fn signature(&self) -> Signature {
         Signature::build("http")
-            .input_output_types(vec![(Type::Nothing, Type::String)])
+            .input_output_types(vec![(Type::Nothing, Type::Any)])
+            // common to get more than help. Get by default
+            .optional(
+                "URL",
+                SyntaxShape::String,
+                "The URL to fetch the contents from.",
+            )
+            // post
+            .optional(
+                "data",
+                SyntaxShape::Any,
+                "The contents of the post body. Required unless part of a pipeline.",
+            )
+            .named(
+                "content-type",
+                SyntaxShape::Any,
+                "the MIME type of content to post",
+                Some('t'),
+            )
+            // common
+            .named(
+                "user",
+                SyntaxShape::Any,
+                "the username when authenticating",
+                Some('u'),
+            )
+            .named(
+                "password",
+                SyntaxShape::Any,
+                "the password when authenticating",
+                Some('p'),
+            )
+            .named(
+                "max-time",
+                SyntaxShape::Duration,
+                "max duration before timeout occurs",
+                Some('m'),
+            )
+            .named(
+                "headers",
+                SyntaxShape::Any,
+                "custom headers you want to add ",
+                Some('H'),
+            )
+            .switch(
+                "raw",
+                "fetch contents as text rather than a table",
+                Some('r'),
+            )
+            .switch(
+                "insecure",
+                "allow insecure server connections when using SSL",
+                Some('k'),
+            )
+            .switch(
+                "full",
+                "returns the full response instead of only the body",
+                Some('f'),
+            )
+            .switch(
+                "allow-errors",
+                "do not fail if the server returns an error code",
+                Some('e'),
+            )
+            .named(
+                "redirect-mode",
+                SyntaxShape::String,
+                "What to do when encountering redirects. Default: 'follow'. Valid options: 'follow' ('f'), 'manual' ('m'), 'error' ('e').",
+                Some('R')
+            )
             .category(Category::Network)
     }
 
@@ -19,7 +91,7 @@ impl Command for Http {
     }
 
     fn extra_description(&self) -> &str {
-        "You must use one of the following subcommands. Using this command as-is will only produce this help message."
+        "Without a subcommand but with a URL provided, it performs a GET request by default or a POST request if data is provided. You can use one of the following subcommands. Using this command as-is will only display this help message."
     }
 
     fn search_terms(&self) -> Vec<&str> {
@@ -33,8 +105,41 @@ impl Command for Http {
         engine_state: &EngineState,
         stack: &mut Stack,
         call: &Call,
-        _input: PipelineData,
+        input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        Ok(Value::string(get_full_help(self, engine_state, stack), call.head).into_pipeline_data())
+        let url = call.opt::<Value>(engine_state, stack, 0)?;
+        let data = call.opt::<Value>(engine_state, stack, 1)?;
+        match (url.is_some(), data.is_some()) {
+            (true, true) => run_post(engine_state, stack, call, input),
+            (true, false) => run_get(engine_state, stack, call, input),
+            (false, true) => Err(ShellError::NushellFailed {
+                msg: (String::from("Default verb is get with a payload. Impossible state")),
+            }),
+            (false, false) => Ok(Value::string(
+                get_full_help(self, engine_state, stack),
+                call.head,
+            )
+            .into_pipeline_data()),
+        }
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Get content from example.com with default verb",
+                example: "http https://www.example.com",
+                result: None,
+            },
+            Example {
+                description: "Post content to example.com with default verb",
+                example: "http https://www.example.com 'body'",
+                result: None,
+            },
+            Example {
+                description: "Get content from example.com with explicit verb",
+                example: "http get https://www.example.com",
+                result: None,
+            },
+        ]
     }
 }

crates/nu-command/src/network/http/post.rs

@@ -161,7 +161,7 @@ struct Arguments {
     redirect: Option<Spanned<String>>,
 }
 
-fn run_post(
+pub fn run_post(
     engine_state: &EngineState,
     stack: &mut Stack,
     call: &Call,