Error using drogon::orm::Result in .csp - data not retrieved

[srikantgudi]

@an-tao

The text is a bit long, so excuse me for that:

I am including the .csp snippet and error log during cmake

.csp snippet:

<%inc
  #include <drogon/drogon.h>
  #include <drogon/orm/Mapper.h>
  #include <iomanip>
  #include <sstream>
%>

<%c++
  using namespace std;
  auto & products = @@.get<drogon::orm::Result()>("products");
%>

looping thru data

<%c++ for (const auto p : products) {
    stringstream sprice("");
    sprice<<setw(10)<<fixed<<setprecision(2)<<stof(p["unitprice"].as<string>());
    %>
    <tr>
      <td align="right"><%c++ $$<<p["productid"].as<int>(); %></td>
      <td><%c++ $$<<p["productname"].as<string>(); %></td>
      <td align="right"><%c++ $$<<sprice.str(); %></td>
      <td align="right"><%c++ $$<<p["reorderlevel"].as<int>(); %></td>
    </tr>
<%c++ } %>

Error log after cmake

[  8%] Building CXX object CMakeFiles/drogapp.dir/products.cc.o
drogapp/build/products.cc: In member function ‘virtual std::string products::genText(const drogon::DrTemplateData&)’:
drogapp/build/products.cc:44:22: error: ‘begin’ was not declared in this scope
   44 |  for (const auto p : products) {
      |                      ^~~~~~~~
drogapp/build/products.cc:44:22: note: suggested alternatives:
In file included from /usr/include/c++/13/string:53,
                 from /usr/local/include/trantor/utils/Date.h:19,
                 from /usr/local/include/trantor/utils/Logger.h:18,
                 from /usr/local/include/drogon/DrClassMap.h:18,
                 from /usr/local/include/drogon/DrObject.h:18,
                 from /usr/local/include/drogon/DrTemplate.h:17,
                 from drogapp/build/products.h:2,
                 from drogapp/build/products.cc:2:
/usr/include/c++/13/bits/range_access.h:114:37: note:   ‘std::begin’
  114 |   template<typename _Tp> const _Tp* begin(const valarray<_Tp>&) noexcept;
      |                                     ^~~~~
In file included from /usr/include/c++/13/filesystem:50,
                 from /usr/local/include/drogon/utils/Utilities.h:29,
                 from drogapp/build/products.cc:4:
/usr/include/c++/13/bits/fs_dir.h:607:3: note:   ‘std::filesystem::__cxx11::begin’
  607 |   begin(recursive_directory_iterator __iter) noexcept
      |   ^~~~~
drogapp/build/products.cc:44:22: error: ‘end’ was not declared in this scope
   44 |  for (const auto p : products) {
      |                      ^~~~~~~~
drogapp/build/products.cc:44:22: note: suggested alternatives:
/usr/include/c++/13/bits/range_access.h:116:37: note:   ‘std::end’
  116 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
      |                                     ^~~
/usr/include/c++/13/bits/fs_dir.h:612:3: note:   ‘std::filesystem::__cxx11::end’
  612 |   end(recursive_directory_iterator) noexcept
      |   ^~~
In file included from /usr/local/include/drogon/DrTemplateBase.h:19,
                 from /usr/local/include/drogon/DrTemplate.h:18:
/usr/local/include/drogon/HttpViewData.h: In instantiation of ‘const T& drogon::HttpViewData::get(const std::string&) const [with T = drogon::orm::Result(); std::string = std::__cxx11::basic_string<char>]’:
drogapp/build/products.cc:31:66:   required from here
/usr/local/include/drogon/HttpViewData.h:40:24: error: variable ‘nullVal’ has function type
   40 |         static const T nullVal = T();
      |                        ^~~~~~~
/usr/local/include/drogon/HttpViewData.h:40:24: error: variable ‘nullVal’ has function type
make[2]: *** [CMakeFiles/drogapp.dir/build.make:244: CMakeFiles/drogapp.dir/products.cc.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:100: CMakeFiles/drogapp.dir/all] Error 2

[an-tao]

@@.get<drogon::orm::Result>("products");
not @@.get<drogon::orm::Result()>("products");

[srikantgudi]

@@.getdrogon::orm::Result("products");

Yes,, while submitting the post I forgot to take off the parentheses ()

I had used it as @@.get<drogon::orm::Result>("products"); but to no avail.

in ProductController.cc (included only the relevant code)

    auto result = clientPtr->execSqlSync("SELECT * FROM products Where categoryid=$1",catid);

    HttpViewData viewData;

    viewData.insert("products", result);

    auto resp = HttpResponse::newHttpViewResponse("products.csp", viewData);

    callback(resp);

In products.csp

<%inc
#include <drogon/drogon.h>
#include <drogon/orm/Mapper.h>
#include
#include
%>
... html code ...

<%c++ for (const auto p : result) {
stringstream sprice("");
sprice<<setw(10)<<fixed<<setprecision(2)<<stof(p["unitprice"].as());
%>

<%c++ $$<<p["productid"].as(); %>
<%c++ $$<<p["productname"].as(); %>
<%c++ $$<<sprice.str(); %>
<%c++ $$<<p["reorderlevel"].as(); %>

<%c++ } %>

Please see the errors line by line, as I cannot make it out:

```         static const T nullVal = T();
In file included from /usr/local/include/drogon/DrTemplateBase.h:19,
                 from /usr/local/include/drogon/DrTemplate.h:18,
                 drogapp/build/products.h:2,
                 drogapp/build/products.cc:2:

/usr/local/include/drogon/HttpViewData.h: In instantiation of ‘const T& drogon::HttpViewData::get(const std::string&) const [with T = drogon::orm::Result; std::string = std::__cxx11::basic_string<char>]’:
drogapp/build/products.cc:29:62:   required from here
/usr/local/include/drogon/HttpViewData.h:40:34: error: no matching function for call to ‘drogon::orm::Result::Result()’
   40 |         static const T nullVal = T();

build/products.cc:17:
/usr/local/include/drogon/orm/Result.h:65:5: note: candidate: ‘drogon::orm::Result::Result(drogon::orm::Result&&)’
   65 |     Result(Result &&) noexcept = default;
      |     ^~~~~~

note:   candidate expects 1 argument, 0 provided
/usr/local/include/drogon/orm/Result.h:64:5: note: candidate: ‘drogon::orm::Result::Result(const drogon::orm::Result&)’

   64 |     Result(const Result &r) noexcept = default;
      |     ^~~~~~
/usr/local/include/drogon/orm/Result.h:64:5: note:   candidate expects 1 argument, 0 provided
/usr/local/include/drogon/orm/Result.h:60:14: note: candidate: ‘drogon::orm::Result::Result(drogon::orm::ResultImplPtr)’

   60 |     explicit Result(ResultImplPtr ptr) : resultPtr_(std::move(ptr))
      |              ^~~~~~

/usr/local/include/drogon/orm/Result.h:60:14: note:   candidate expects 1 argument, 0 provided

Let me know the issue and what changes I need to make.

NOTE: I reverted to using models and creating vector of models. However, I would still like to know the optimum way.
Also, in another post, I have put my suggestions.

Thanks.

[srikantgudi]

@an-tao

I used as follows and it worked:

Controller.cc

    std::vector<drogon::orm::Row> vproducts;
    for (auto & row : result) {
      vproducts.push_back(row);
    }
    // Insert into view
    HttpViewData viewData;
    viewData.insert("products", vproducts);
    auto resp = HttpResponse::newHttpViewResponse("products.csp", viewData);
    callback(resp);

In products.csp

<%inc
  #include <drogon/drogon.h>
  #include <drogon/orm/Mapper.h>
  #include <iomanip>
  #include <sstream>
%>

<%c++
  using namespace std;
  using namespace drogon;
  
  auto products = @@.get<std::vector<drogon::orm::Row>>("products");
%>

and for each field as <%c++ $$<<p["field_name"].c_str()

I had gone thru the drogon::row::Field.h and drogon::orm::Result.h

Can you provide std::vector getRows() in the Result.h to return vector<drogon::orm::Row> ?

so that in the code we can directly retrieve as auto data = result.getRows(), and pass the same to the .csp file.

Just an idea !