Ok got it, it seems to me the best way is to just treat is as a string
because std::string can handle embedded nul bytes. Thanks!
On Thursday, December 3, 2020 at 4:17:08 PM UTC tobias.krueger wrote:
> > I can store it in my key-value store as a string too
>
> It is hard to tell as we know nothing about your store.
> A char pointer is just an address into your memory. It has no information
> about the size of the block.
> If you interpret this pointer as a character string, the convention is
> that this string ends with the very first nul byte.
> If it is the address a blob, no one can tell how long it is.
> But this actually has nothing to do the with GRPC - this is very basic
> string/memory handling of C++
>
> On Thursday, December 3, 2020 at 5:10:49 PM UTC+1 Joseph Liu wrote:
>
>> So basically, send val as a string, and even when we receive it on the
>> server side, I can store it in my key-value store as a string too? (Right
>> now I'm storing it as a char*)
>>
>> On Thursday, December 3, 2020 at 4:04:02 PM UTC tobias.krueger wrote:
>>
>>> The std::string, which is used as the container for the grpc datatype
>>> "bytes", can handle embedded nul bytes.
>>> But In your "Put" method you pass the parameter "val" as char * pointer.
>>> This char * pointer will be converted to a std::string terminating with
>>> the first occurrence of the nul byte.
>>>
>>> So must either past the value "val" as std::string or std::vector<char>
>>>
>>> HTH
>>> Tobias
>>>
>>> On Thursday, December 3, 2020 at 4:59:05 PM UTC+1 Joseph Liu wrote:
>>>
>>>> So I'm using gRPC to store data in a key-value store.
>>>>
>>>> The protos look like this:
>>>>
>>>> syntax = "proto3";
>>>>
>>>> package keyvaluestore;
>>>>
>>>> service KeyValueStore {
>>>> rpc AddUser(Credentials) returns (Response) {}
>>>> rpc Get(Request) returns (Response) {}
>>>> rpc Put(Request) returns (Response) {}
>>>> rpc Cput(Request) returns (Response) {}
>>>> rpc Delete(Request) returns (Response) {}
>>>> }
>>>>
>>>> message Credentials {
>>>> string user = 1;
>>>> string passwd = 2;
>>>> }
>>>>
>>>> message Request {
>>>> string user = 1;
>>>> string key = 2;
>>>> bytes val = 3;
>>>> bytes val2 = 4;
>>>> string addr = 5;
>>>> }
>>>>
>>>> message Response {
>>>> bytes val = 1;
>>>> uint32 nbytes = 2;
>>>> string message = 3;
>>>> }
>>>>
>>>> Right now, the issue is that if we send over say, an image as byte data
>>>> which can include the null byte, then when the server receives it in the
>>>> `Request` object, it treats it as a string; when it does this it only
>>>> reads
>>>> it up the the first null byte.
>>>>
>>>> How we pack the `Request` object on the client side:
>>>>
>>>> bool KeyValueStoreClient::Put(const string& user, const string&
>>>> key, const char* val) {
>>>> Request req;
>>>> req.set_user(user);
>>>> req.set_key(key);
>>>> req.set_val(val);
>>>>
>>>> ClientContext ctx;
>>>> Response res;
>>>> Status status = stub_->Put(&ctx, req, &res);
>>>> }
>>>>
>>>> Server receives `req->val()` as a string instead of `char*`:
>>>>
>>>> Status KeyValueStoreServiceImpl::Put(ServerContext* ctx, const
>>>> Request* req, Response* res) {
>>>> // req->val() is a string
>>>>
>>>> }
>>>>
>>>>
>>>>
>>>>
>>>>
--
You received this message because you are subscribed to the Google Groups
"grpc.io" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/grpc-io/fa2f843a-7155-43d4-a5ec-f9ed5b59a86en%40googlegroups.com.
