Reqwest - how to create a query string with parameters that don't have explicit values

help
1

For example, to create https://www.google.com/?foo=bar I can do

use reqwest::Client;

fn main() {
    let client = Client::builder().build().unwrap();
    let req = client.get("https://www.google.com").query(&[("foo", "bar")]).build().unwrap();
    println!("{}", req.url());
}

But how do I create https://www.google.com/?foo? (notice the missing =bar). And yes, these URIs are valid: stackoverflow question and answer.

I know I can create it with direct string manipulation, but I want to know if it's possible to create using the RequestBuilder or URL methods provided in the library.

2

Currently you cannot through reqwest's API, there is no code path that calls through to form_urlencoded::Serializer::append_key_only. Note there is an intermediate serde_urlencoded crate that needs to also be updated to call through to form_urlencoded if you want to add support.

If you depend on form_urlencoded directly (because it's not re-exported through reqwest), you can do:

let mut req = client.get("https://www.google.com").build().unwrap();

let query: String = form_urlencoded::Serializer::new(String::new())
    .append_key_only("foo")
    .finish();
req.url_mut().set_query(Some(&query));

But I guess that's not very different from setting it through a String yourself.

3

Thanks for pointing out where the query string is being serialized. But yes, that becomes so verbose that I might as well simply create the URL from a String.

4

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