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61 lines
1.9 KiB
Markdown
61 lines
1.9 KiB
Markdown
---
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title: "C01. Get the Response Body / Save to a File"
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order: 1
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status: "draft"
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---
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## Get it as a string
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```cpp
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httplib::Client cli("http://localhost:8080");
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auto res = cli.Get("/hello");
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if (res && res->status == 200) {
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std::cout << res->body << std::endl;
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}
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```
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`res->body` is a `std::string`, ready to use as-is. The entire response is loaded into memory.
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> **Warning:** If you fetch a large file with `res->body`, it all goes into memory. For large downloads, use a `ContentReceiver` as shown below.
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## Save to a file
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```cpp
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httplib::Client cli("http://localhost:8080");
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std::ofstream ofs("output.bin", std::ios::binary);
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if (!ofs) {
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std::cerr << "Failed to open file" << std::endl;
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return 1;
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}
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auto res = cli.Get("/large-file",
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[&](const char *data, size_t len) {
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ofs.write(data, len);
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return static_cast<bool>(ofs);
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});
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```
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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.
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Return `false` from the callback to abort the download. In the example above, if writing to `ofs` fails, the download stops automatically.
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> **Detail:** Want to check response headers like Content-Length before downloading? Combine a `ResponseHandler` with a `ContentReceiver`.
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>
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> ```cpp
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> auto res = cli.Get("/large-file",
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> [](const httplib::Response &res) {
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> auto len = res.get_header_value("Content-Length");
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> std::cout << "Size: " << len << std::endl;
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> return true; // return false to skip the download
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> },
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> [&](const char *data, size_t len) {
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> ofs.write(data, len);
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> return static_cast<bool>(ofs);
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> });
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> ```
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>
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> The `ResponseHandler` is called after headers arrive but before the body. Return `false` to skip the download entirely.
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> To show download progress, see [C11. Use the progress callback](../c11-progress-callback).
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