c++ - 如何将从文件上传小部件上传的假脱机文件传递到 C FILE *f 指针

Question

我需要传递一些从 Wt 文件上传小部件上传的文本文件，作为某些 C 函数的参数来处理其数据。除非我真的找不到使用假脱机文件名(从 std::string 转换为 char *)作为第一个 fopen() 参数来打开文件的正确方法，否则我意识到我还没有理解Wt 提供的文件处理方法。即，假脱机文件存储在哪里？我尝试在文件上传完成后使用 std::string WtFileUpload::spoolFileName() const (我提供了一个在进度条到达末尾时单击的按钮)，但是通过挖掘errno号，我发现该文件不存在。

请建议我一种正确的方法来继续此操作(如果可以的话，请提供一些代码)并帮助我了解 Wt 处理使用此小部件上传的文件的方式。

提前致谢。

更新:我的文件上传和处理代码:

//Declared in the application class:
Wt::WFileUpload *RORUpload;
Wt::WPushButton *RORUploadButton;

//Create file upload widget and add handlers for it in application constructor:
root()->addWidget(new Wt::WText("RINEX File Loaders "));
new Wt::WBreak(root());
//RINEX observation data file from rover station uploader.
new Wt::WBreak(root());
RORUpload = new Wt::WFileUpload();
RORUpload->setFileTextSize(40);
root()->addWidget(new Wt::WText("RINEX Rover Observation Data "));
new Wt::WBreak(root());
RORUploadButton = new Wt::WPushButton("Upload", root());
root()->addWidget(RORUpload);
//Upload when the button is clicked.
RORUploadButton->clicked().connect(RORUpload, &Wt::WFileUpload::upload);
RORUploadButton->clicked().connect(RORUploadButton, &Wt::WPushButton::disable);
// Upload automatically when the user entered a file.
RORUpload->changed().connect(RORUpload, &Wt::WFileUpload::upload); // !!! do not rename this 'upload'
RORUpload->changed().connect(RORUploadButton, &Wt::WPushButton::disable);
// React to a succesfull upload.
RORUpload->uploaded().connect(RORUpload, (Wt::WObject::Method) &Wt::WFileUpload::uploaded);
//React to a fileupload problem.
RORUpload->fileTooLarge().connect(RORUpload, (Wt::WObject::Method) &Wt::WFileUpload::fileTooLarge);

//When user presses a "submit" button, a connection function will be called.
const std::string Nameofror = RORUpload->spoolFileName();
const char *CNameofror = Nameofror.c_str();

我想知道问题是否与我的 (Wt::WObjectMethod) 转换有关。 编辑:请参阅我对此问题的评论。

更新 2:忘了说，当我单击“提交”按钮时，程序崩溃了 代码:

//Create button into application constructor:
  SubmitButton = new Wt::WPushButton("Submit", root());
SubmitButton->clicked().connect(SubmitButton, &Wt::WPushButton::disable);
SubmitButton->clicked().connect(this, &GOPApplication::definedOptions);

//definedOptions:

void GOPApplication::definedOptions()
{

int Posmode = PTGroup->checkedId();  //Value selection from PTContainer (checked radio button id).

     //int singlemoving;                                              //Value selection from SPContainer (checked radio button id).
int Frequencies = FGroup->checkedId();                  //Value selection from FContainer (checked radio button id).
const Wt::WString WElmask = EMedit->text();             //Value selection from EMw (given number).
std::string SElmask = WElmask.narrow();                 //Value selection from EMw (given number).
const char *CElmask = SElmask.c_str();                  //Value selection from EMw (given number).
float Elmask = atof(CElmask);                           //Value selection from EMw (given number).
int Height = HGroup->checkedId();                       //Value selection from HContainer (checked radio button id).
int Soltype = STGroup->checkedId();                     //Value selection from STContainer (checked radio button id).
int Sateph = SAGroup->checkedId();                      //Value selection from SEContainer (checked radio button id).
int Basestatcoord = BSCGroup->checkedId();              //Value selection from BSCContainer (checked radio button id).
int Ionerror = IEGroup->checkedId();                    //Value selection from IEContainer (checked radio button id).
int Troperror = TEGroup->checkedId();                   //Value selection from TEContainer (checked radio button id).
int Receiverapcpvc = RAGroup->checkedId();              //Value selection from RAContainer (checked radio button id).
int Satelliteapvc = SAGroup->checkedId();               //Value selection from SAContainer (checked radio button id).
int Earthtidescorr = ETCGroup->checkedId();             //Value selection from ETCContainer (checked radio button id).
int Ambresstr = STRGroup->checkedId();                  //Value selection from STRContainer (checked radio button id).
const Wt::WString WMinlockcount = MLCedit->text();      //Value selection from MLCw (given number).
std::string SMinlockcount = WMinlockcount.narrow();     //Value selection from MLCw (given number).
const char *CMinlockcount = SMinlockcount.c_str();      //Value selection from MLCw (given number).
float Minlockcount = atof(CMinlockcount);               //Value selection from MLCw (given number).
const Wt::WString WMinfixcount = MFCedit->text();       //Value selection from MFCw (given number).
std::string SMinfixcount = WMinfixcount.narrow();       //Value selection from MFCw (given number).
const char *CMinfixcount = SMinfixcount.c_str();        //Value selection from MFCw (given number).
float Minfixcount = atof(CMinfixcount);                 //Value selection from MFCw (given number)
const Wt::WString WThreshold = Tedit->text();           //Value selection from Tw (given number).
std::string SThreshold = WThreshold.narrow();           //Value selection from Tw (given number).
const char *CThreshold = SThreshold.c_str();            //Value selection from Tw (given number).
float Threshold = atof(CThreshold);                     //Value selection from Tw (given number).
const Wt::WString WMinelevangle = MEAedit->text();      //Value selection from MEAw (given number).
std::string SMinelevangle = WMinelevangle.narrow();     //Value selection from Tw (given number).
const char *CMinelevangle = SMinelevangle.c_str();      //Value selection from Tw (given number).
float Minelevangle = atof(CMinelevangle);               //Value selection from Tw (given number).
int Settimesystem = STSGroup->checkedId();              //Value selection from STSContainer (checked radio button id).
int Outputresiduals = ORGroup->checkedId();             //Value selection from ORContainer (checked radio button id).
int Settimeformat = STFGroup->checkedId();              //Value selection from STFContainer (checked radio button id).
//What about RINEX files obtaining?
//Maybe... (see notebook for infos about spoolFileName() usage)
const std::string Nameofror = RORUpload->spoolFileName();
const char *CNameofror = Nameofror.c_str();
printf("\n\n============= %s =============\n\n", CNameofror);
//const std::string Nameofrob = ROBUpload->spoolFileName();
//const char *CNameofrob = Nameofrob.c_str();
//const std::string Nameofrn = RNUpload->spoolFileName();
//const char *CNameofrn = Nameofrn.c_str();
//post-processing(Posmode,Frequencies,Elmask,Height,Soltype,Sateph,Basestatcoord,Ionerror,Troperror,Receiverapcpvc,
//              Satelliteapvc,Earthtidescor,Ambresstr,Minlockcount,Minfixcount,Threshold,Minelevangle,Settimesystem,Outputresiduals,Settimeformat);
 }

Answer 1

您确定文件上传过程已完成吗？如果这是真的，那么您应该仅在代码中的某个位置收到信号WFileUpload::uploaded() 或 WFileUpload::fileTooLarge() 后才尝试使用文件。请检查一下。