Where did the default Useragent of Cobalt come from? - cobalt

Question

When run the cobalt, I can see the useragent from the log:
[0101/000230:INFO:application.cc(690)] User Agent: Mozilla/5.0 (DirectFB; Linux x86_64) Cobalt/4.13031-qa (unlike Gecko) Starboard/1
So where does it come from? Is there a way to change it?

Answer 1

The default useragent is set in the following file, you can have a check:
https://cobalt.googlesource.com/cobalt/+/e9b4b99dab6e774b8b6e63add74c352cc5dd395a/src/cobalt/network/user_agent_string_factory.cc
std::string UserAgentStringFactory::CreateUserAgentString() {
// Cobalt's user agent contains the following sections:
// Mozilla/5.0 (ChromiumStylePlatform)
// Cobalt/Version.BuildNumber-BuildConfiguration (unlike Gecko)
// Starboard/APIVersion,
// Device/FirmwareVersion (Brand, Model, ConnectionType)
// Mozilla/5.0 (ChromiumStylePlatform)
std::string user_agent =
base::StringPrintf("Mozilla/5.0 (%s)", CreatePlatformString().c_str());
// Cobalt/Version.BuildNumber-BuildConfiguration (unlike Gecko)
base::StringAppendF(&user_agent, " Cobalt/%s.%s-%s (unlike Gecko)",
COBALT_VERSION, COBALT_BUILD_VERSION_NUMBER,
kBuildConfiguration);
// Starboard/APIVersion,
if (!starboard_version_.empty()) {
base::StringAppendF(&user_agent, " %s", starboard_version_.c_str());
}
// Device/FirmwareVersion (Brand, Model, ConnectionType)
if (youtube_tv_info_) {
base::StringAppendF(
&user_agent, ", %s_%s_%s/%s (%s, %s, %s)",
youtube_tv_info_->network_operator.value_or("").c_str(),
CreateDeviceTypeString().c_str(),
youtube_tv_info_->chipset_model_number.value_or("").c_str(),
youtube_tv_info_->firmware_version.value_or("").c_str(),
youtube_tv_info_->brand.c_str(), youtube_tv_info_->model.c_str(),
CreateConnectionTypeString().c_str());
}
return user_agent;
}

Answer 2

If your SbSystemGetDeviceType() is true for SystemDeviceTypeIsTv() (in file user_agent_string_factory_starboard.cc), you can customize the UA by implementing some fields of SbSystemGetProperty() + some SbSystemGet() functions.
This is a typical example:
Mozilla/5.0 (1) Cobalt/11.119147-gold (unlike Gecko) Starboard/8, 2_8_6/5 (3, 4, 7)
where,
kSbSystemPropertyPlatformName
kSbSystemPropertyNetworkOperatorName
kSbSystemPropertyManufacturerName
kSbSystemPropertyModelName
kSbSystemPropertyFirmwareVersion
kSbSystemPropertyChipsetModelNumber
SbSystemGetConnectionType()
SbSystemGetDeviceType()