问题描述
我在laravel中遇到错误。我正在使用laravel 5.8。我正在使用dompdf从刀片生成pdf。它在localhost中工作正常，但是在服务器中给出了错误。 503服务不可用
解决方法
Composer 提供了将 Php 扩展指示为依赖项的能力，而不仅仅是包。它无法安装这些，但如果您的服务器环境不支持您的应用程序，它确实给了它一个大声尖叫的机会。我敢打赌，如果您将 #include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
/* structure to hold all the data for a matrix. See discussion
* in comments to understand this structure. */
struct matrix {
int m_rows,m_cols;
double **m_data;
double *unused_1; /* not used. Only to warrant the
* alignment to double * values. */
double unused_2; /* same as before. */
};
/* this are simple providers of matrix data,depending on how we
* want to initialize the matrix. */
/* initializes each element to a constant provided by reference
*/
double prov_const(void *cb_par,int row,int col)
{
double *val_ref = cb_par;
return *val_ref;
}
double prov_list(void *cb_par,int col)
{
double **p = cb_par;
return *(*p)++;
}
double prov_copy(void *cb_par,int col)
{
struct matrix *src = cb_par;
assert(row < src->m_rows && col < src->m_cols);
return src->m_data[row][col];
}
/* initializes kroneker matrix. Identity */
double prov_ident(void *unused,int col)
{
return row == col ? 1.0 : 0.0;
}
/* provides elements from file stream */
double prov_file(void *cb_par,int col)
{
FILE *in = cb_par;
double ret_val;
if (isatty(fileno(in))) {
fprintf(stderr,"mat[%d][%d]: ",row,col);
fflush(stderr);
}
int res = fscanf(in,"%lg",&ret_val);
assert(res == 1);
return ret_val;
}
/* this creates the whole matrix with just one malloc */
struct matrix *mat_creat(
int rows,int cols,/* dimensions */
double prov(void *cd,int col),/* initializer */
void *cd) /* initializer callback data */
{
size_t total_cells = rows * cols;
/* See discussion about alignment in the comments to
* understand the code below. */
struct matrix *ret_val = malloc(
sizeof *ret_val
+ rows * sizeof *ret_val->m_data
+ total_cells * sizeof **ret_val->m_data);
assert(ret_val != NULL);
/* place the array with bigger element cell first,* to warrant the smaller data alignment */
double **aux1; /* pointer to array of row pointers */
double *aux2; /* pointer to array of double cells */
if (sizeof *ret_val->m_data > sizeof **ret_val->m_data) {
/* put the pointers to rows first,pointer is bigger */
aux1 = (double **) (ret_val + 1); /* row pointers array */
aux2 = (double *) (aux1 + rows); /* double row arrays */
} else {
/* put the cells first,double is bigger than pointer */
aux2 = (double *) (ret_val + 1);
aux1 = (double **) (aux2 + total_cells);
}
ret_val->m_rows = rows;
ret_val->m_cols = cols;
ret_val->m_data = aux1;
/* start the build */
for (int row = 0; row < rows; row++) {
*aux1++ = aux2; /* the pointer to the row */
if (prov) {
for (int col = 0; col < cols; col++) {
/* this provides each element of the row */
*aux2++ = prov(cd,col);
}
} else {
/* no provider,no cell initialization */
aux2 += cols;
}
}
return ret_val;
}
struct matrix *mat_add(struct matrix *dst,struct matrix *b)
{
assert(dst->m_rows == b->m_rows
&& dst->m_cols == b->m_cols);
for (int row = 0; row < dst->m_rows; row++) {
for (int col = 0; col < dst->m_cols; col++) {
dst->m_data[row][col] += b->m_data[row][col];
}
}
return dst;
}
struct matrix *mat_mscalar(struct matrix *dst,double b)
{
for (int row = 0; row < dst->m_rows; row++) {
for (int col = 0; col < dst->m_cols; col++) {
dst->m_data[row][col] *= b;
}
}
return dst;
}
struct matrix *mat_prod(struct matrix *a,struct matrix *b)
{
assert(a->m_cols == b->m_rows);
struct matrix *ret_val
= mat_creat(a->m_rows,b->m_cols,NULL,NULL);
for(int row = 0; row < a->m_rows; row++) {
for (int col = 0; col < b->m_cols; col++) {
double accum = 0.0;
for (int k = 0; k < a->m_cols; k++) {
accum += a->m_data[row][k]
* b->m_data[k][col];
}
ret_val->m_data[row][col] = accum;
}
}
return ret_val;
}
trix *mat_pow(struct matrix *a,unsigned N)
{
/* ensure matrix is square */
assert(a->m_rows == a->m_cols);
struct matrix *ret_val
= mat_creat(a->m_rows,a->m_cols,prov_ident,NULL);
if (N == 0) return ret_val; /* a**0 -> I */
/* search for most significant bit */
unsigned bit = 0;
while ((1 << bit) < N) bit++;
bit = 1 << bit;
while (bit) {
/* square it */
struct matrix *aux = mat_prod(ret_val,ret_val);
free(ret_val); /* must free after multiplying */
ret_val = aux; /* assign the new matrix. */
if (bit & N) { /* multiply by a */
aux = mat_prod(ret_val,a);
free(ret_val);
ret_val = aux;
}
bit >>= 1;
}
return ret_val;
}
ssize_t mat_print(struct matrix *m,FILE *out,char *fmt)
{
#define ACT() do{ \
if (n < 0) { \
return n; \
} else { \
ret_val += n; \
} \
} while (0)
ssize_t ret_val = 0,n;
char *sep1 = "{";
for (int row = 0; row < m->m_rows; row++) {
n = fprintf(out,"%s",sep1);
ACT();
sep1 = ",\n ";
char *sep2 = "{";
for (int col = 0; col < m->m_cols; col++) {
n = fprintf(out,sep2);
ACT();
sep2 = ",";
n = fprintf(out,fmt,m->m_data[row][col]);
ACT();
}
n = fprintf(out,"}");
ACT();
}
n = fprintf(out,"}\n");
ACT();
return ret_val;
}
int main(int argc,char **argv)
{
static double values[] = {
1.0,2.0,3.0,4.0,0.0,1.0,5.0,6.0,7.0,};
static double coefs[] = {
1.0,-4.0,};
static double zero = 0.0;
double *p = values;
struct matrix *M = mat_creat(4,4,prov_list,&p);
printf("M =\n");
mat_print(M,stdout,"%g");
struct matrix *P = mat_creat(4,prov_const,&zero);
printf("P[M] = ");
for (int coef = 0; coef <= 4; coef++) {
if (coef) {
if (coefs[coef] > 0.0) {
printf(" +");
} else {
printf(" ");
}
}
printf("%g * %s",coefs[coef],coef ? "A" : "I");
if (coef > 1) {
printf("^%d",coef);
}
}
printf(" =\n");
for (int coef = 0; coef <= 4; coef++) {
printf("M\n");
mat_print(M,"%g");
printf("**%d\n",coef);
struct matrix *TN = mat_pow(M,coef);
mat_print(TN,"%g");
TN = mat_mscalar(TN,coefs[coef]);
printf("*%lg\n",coefs[coef]);
mat_print(TN,"%g");
P = mat_add(P,TN);
printf("+\n");
mat_print(P,"%g");
free(TN);
}
free(P);
free(M);
}
添加到它并运行 ext-dom 它会失败。某些 IDE 甚至会在需要时提示您添加类似内容。
说了这么多，请确保安装了 php xml extension。还要检查您在 composer install 中的错误日志。