lix/src/libfetchers/github.cc

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2020-04-08 12:12:22 +00:00
#include "filetransfer.hh"
#include "cache.hh"
#include "fetchers.hh"
#include "globals.hh"
#include "store-api.hh"
#include <nlohmann/json.hpp>
namespace nix::fetchers {
std::regex ownerRegex("[a-zA-Z][a-zA-Z0-9_-]*", std::regex::ECMAScript);
std::regex repoRegex("[a-zA-Z][a-zA-Z0-9_-]*", std::regex::ECMAScript);
struct GitHubInput : Input
{
std::string owner;
std::string repo;
std::optional<std::string> ref;
std::optional<Hash> rev;
std::string type() const override { return "github"; }
bool operator ==(const Input & other) const override
{
auto other2 = dynamic_cast<const GitHubInput *>(&other);
return
other2
&& owner == other2->owner
&& repo == other2->repo
&& rev == other2->rev
&& ref == other2->ref;
}
bool isImmutable() const override
{
return (bool) rev || narHash;
}
std::optional<std::string> getRef() const override { return ref; }
std::optional<Hash> getRev() const override { return rev; }
ParsedURL toURL() const override
{
auto path = owner + "/" + repo;
assert(!(ref && rev));
if (ref) path += "/" + *ref;
if (rev) path += "/" + rev->to_string(Base16, false);
return ParsedURL {
.scheme = "github",
.path = path,
};
}
Attrs toAttrsInternal() const override
{
Attrs attrs;
attrs.emplace("owner", owner);
attrs.emplace("repo", repo);
if (ref)
attrs.emplace("ref", *ref);
if (rev)
attrs.emplace("rev", rev->gitRev());
return attrs;
}
std::pair<Tree, std::shared_ptr<const Input>> fetchTreeInternal(nix::ref<Store> store) const override
{
auto rev = this->rev;
auto ref = this->ref.value_or("master");
if (!rev) {
auto url = fmt("https://api.github.com/repos/%s/%s/commits/%s",
owner, repo, ref);
auto json = nlohmann::json::parse(
readFile(
store->toRealPath(
downloadFile(store, url, "source", false).storePath)));
rev = Hash(std::string { json["sha"] }, htSHA1);
debug("HEAD revision for '%s' is %s", url, rev->gitRev());
}
auto input = std::make_shared<GitHubInput>(*this);
input->ref = {};
input->rev = *rev;
Attrs immutableAttrs({
{"type", "git-tarball"},
{"rev", rev->gitRev()},
});
if (auto res = getCache()->lookup(store, immutableAttrs)) {
return {
Tree{
.actualPath = store->toRealPath(res->second),
.storePath = std::move(res->second),
.info = TreeInfo {
.lastModified = getIntAttr(res->first, "lastModified"),
},
},
input
};
}
// FIXME: use regular /archive URLs instead? api.github.com
// might have stricter rate limits.
auto url = fmt("https://api.github.com/repos/%s/%s/tarball/%s",
owner, repo, rev->to_string(Base16, false));
std::string accessToken = settings.githubAccessToken.get();
if (accessToken != "")
url += "?access_token=" + accessToken;
auto tree = downloadTarball(store, url, "source", true);
getCache()->add(
store,
immutableAttrs,
{
{"rev", rev->gitRev()},
{"lastModified", *tree.info.lastModified}
},
tree.storePath,
true);
return {std::move(tree), input};
}
};
struct GitHubInputScheme : InputScheme
{
std::unique_ptr<Input> inputFromURL(const ParsedURL & url) override
{
if (url.scheme != "github") return nullptr;
auto path = tokenizeString<std::vector<std::string>>(url.path, "/");
auto input = std::make_unique<GitHubInput>();
if (path.size() == 2) {
} else if (path.size() == 3) {
if (std::regex_match(path[2], revRegex))
input->rev = Hash(path[2], htSHA1);
else if (std::regex_match(path[2], refRegex))
input->ref = path[2];
else
throw BadURL("in GitHub URL '%s', '%s' is not a commit hash or branch/tag name", url.url, path[2]);
} else
throw BadURL("GitHub URL '%s' is invalid", url.url);
for (auto &[name, value] : url.query) {
if (name == "rev") {
if (input->rev)
throw BadURL("GitHub URL '%s' contains multiple commit hashes", url.url);
input->rev = Hash(value, htSHA1);
}
else if (name == "ref") {
if (!std::regex_match(value, refRegex))
throw BadURL("GitHub URL '%s' contains an invalid branch/tag name", url.url);
if (input->ref)
throw BadURL("GitHub URL '%s' contains multiple branch/tag names", url.url);
input->ref = value;
}
}
if (input->ref && input->rev)
throw BadURL("GitHub URL '%s' contains both a commit hash and a branch/tag name", url.url);
input->owner = path[0];
input->repo = path[1];
return input;
}
std::unique_ptr<Input> inputFromAttrs(const Attrs & attrs) override
{
if (maybeGetStrAttr(attrs, "type") != "github") return {};
for (auto & [name, value] : attrs)
if (name != "type" && name != "owner" && name != "repo" && name != "ref" && name != "rev")
throw Error("unsupported GitHub input attribute '%s'", name);
auto input = std::make_unique<GitHubInput>();
input->owner = getStrAttr(attrs, "owner");
input->repo = getStrAttr(attrs, "repo");
input->ref = maybeGetStrAttr(attrs, "ref");
if (auto rev = maybeGetStrAttr(attrs, "rev"))
input->rev = Hash(*rev, htSHA1);
return input;
}
};
static auto r1 = OnStartup([] { registerInputScheme(std::make_unique<GitHubInputScheme>()); });
}