mirror of
https://github.com/yhirose/cpp-httplib.git
synced 2026-04-12 11:48:30 +00:00
61 lines
1.9 KiB
Markdown
61 lines
1.9 KiB
Markdown
---
|
|
title: "C01. Get the Response Body / Save to a File"
|
|
order: 1
|
|
status: "draft"
|
|
---
|
|
|
|
## Get it as a string
|
|
|
|
```cpp
|
|
httplib::Client cli("http://localhost:8080");
|
|
auto res = cli.Get("/hello");
|
|
if (res && res->status == 200) {
|
|
std::cout << res->body << std::endl;
|
|
}
|
|
```
|
|
|
|
`res->body` is a `std::string`, ready to use as-is. The entire response is loaded into memory.
|
|
|
|
> **Warning:** If you fetch a large file with `res->body`, it all goes into memory. For large downloads, use a `ContentReceiver` as shown below.
|
|
|
|
## Save to a file
|
|
|
|
```cpp
|
|
httplib::Client cli("http://localhost:8080");
|
|
|
|
std::ofstream ofs("output.bin", std::ios::binary);
|
|
if (!ofs) {
|
|
std::cerr << "Failed to open file" << std::endl;
|
|
return 1;
|
|
}
|
|
|
|
auto res = cli.Get("/large-file",
|
|
[&](const char *data, size_t len) {
|
|
ofs.write(data, len);
|
|
return static_cast<bool>(ofs);
|
|
});
|
|
```
|
|
|
|
With a `ContentReceiver`, data arrives in chunks. You can write each chunk straight to disk without buffering the whole body in memory — perfect for large file downloads.
|
|
|
|
Return `false` from the callback to abort the download. In the example above, if writing to `ofs` fails, the download stops automatically.
|
|
|
|
> **Detail:** Want to check response headers like Content-Length before downloading? Combine a `ResponseHandler` with a `ContentReceiver`.
|
|
>
|
|
> ```cpp
|
|
> auto res = cli.Get("/large-file",
|
|
> [](const httplib::Response &res) {
|
|
> auto len = res.get_header_value("Content-Length");
|
|
> std::cout << "Size: " << len << std::endl;
|
|
> return true; // return false to skip the download
|
|
> },
|
|
> [&](const char *data, size_t len) {
|
|
> ofs.write(data, len);
|
|
> return static_cast<bool>(ofs);
|
|
> });
|
|
> ```
|
|
>
|
|
> The `ResponseHandler` is called after headers arrive but before the body. Return `false` to skip the download entirely.
|
|
|
|
> To show download progress, see [C11. Use the progress callback](c11-progress-callback).
|