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#pragma once
#include "types.hh"
#include "hash.hh"
#include "globals.hh"
#include <string>
#include <future>
namespace nix {
struct DownloadSettings : Config
{
Setting<bool> enableHttp2{this, true, "http2",
"Whether to enable HTTP/2 support."};
Setting<std::string> userAgentSuffix{this, "", "user-agent-suffix",
"String appended to the user agent in HTTP requests."};
Setting<size_t> httpConnections{this, 25, "http-connections",
"Number of parallel HTTP connections.",
{"binary-caches-parallel-connections"}};
Setting<unsigned long> connectTimeout{this, 0, "connect-timeout",
"Timeout for connecting to servers during downloads. 0 means use curl's builtin default."};
Setting<unsigned int> tries{this, 5, "download-attempts",
"How often Nix will attempt to download a file before giving up."};
};
extern DownloadSettings downloadSettings;
struct DownloadRequest
{
std::string uri;
std::string expectedETag;
bool verifyTLS = true;
bool head = false;
size_t tries = downloadSettings.tries;
unsigned int baseRetryTimeMs = 250;
ActivityId parentAct;
bool decompress = true;
std::shared_ptr<std::string> data;
std::string mimeType;
std::function<void(char *, size_t)> dataCallback;
DownloadRequest(const std::string & uri)
: uri(uri), parentAct(getCurActivity()) { }
std::string verb()
{
return data ? "upload" : "download";
}
};
struct DownloadResult
{
bool cached = false;
std::string etag;
std::string effectiveUrl;
std::shared_ptr<std::string> data;
uint64_t bodySize = 0;
};
struct CachedDownloadResult
{
// Note: 'storePath' may be different from 'path' when using a
// chroot store.
Path storePath;
Path path;
std::optional<std::string> etag;
};
class Store;
struct Downloader
{
/* Enqueue a download request, returning a future to the result of
the download. The future may throw a DownloadError
exception. */
virtual void enqueueDownload(const DownloadRequest & request,
Callback<DownloadResult> callback) = 0;
std::future<DownloadResult> enqueueDownload(const DownloadRequest & request);
/* Synchronously download a file. The request will be retried in
case of transient failures. */
DownloadResult download(const DownloadRequest & request);
/* Download a file, writing its data to a sink. The sink will be
invoked on the thread of the caller. The request will not be
retried in case of transient failures. */
void download(DownloadRequest && request, Sink & sink);
/* Check if the specified file is already in ~/.cache/nix/tarballs
and is more recent than ‘tarball-ttl’ seconds. Otherwise,
use the recorded ETag to verify if the server has a more
recent version, and if so, download it to the Nix store. */
CachedDownloadResult downloadCached(
ref<Store> store, const string & uri, bool unpack, string name = "",
const Hash & expectedHash = Hash(), string * effectiveUri = nullptr,
int ttl = settings.tarballTtl);
enum Error { NotFound, Forbidden, Misc, Transient, Interrupted };
};
/* Return a shared Downloader object. Using this object is preferred
because it enables connection reuse and HTTP/2 multiplexing. */
ref<Downloader> getDownloader();
/* Return a new Downloader object. */
ref<Downloader> makeDownloader();
class DownloadError : public Error
{
public:
Downloader::Error error;
DownloadError(Downloader::Error error, const FormatOrString & fs)
: Error(fs), error(error)
{ }
bool isTransient() override
{
return error == Downloader::Error::Transient;
}
};
bool isUri(const string & s);
}
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